1
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Halder A, Nell D, Sihi A, Bajaj A, Sanvito S, Droghetti A. Half-Metallic Transport and Spin-Polarized Tunneling through the van der Waals Ferromagnet Fe 4GeTe 2. NANO LETTERS 2024; 24:9221-9228. [PMID: 39037057 PMCID: PMC11299226 DOI: 10.1021/acs.nanolett.4c01479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 07/08/2024] [Accepted: 07/08/2024] [Indexed: 07/23/2024]
Abstract
We examine the coherent spin-dependent transport properties of the van der Waals (vdW) ferromagnet Fe4GeTe2 using density functional theory combined with the nonequilibrium Green's function method. Our findings reveal that the conductance perpendicular to the layers is half-metallic, meaning that it is almost entirely spin-polarized. This property persists from the bulk to a single layer, even under significant bias voltages and with spin-orbit coupling. Additionally, using dynamical mean field theory for quantum transport, we demonstrate that electron correlations are important for magnetic properties but minimally impact the conductance, preserving almost perfect spin-polarization. Motivated by these results, we then study the tunnel magnetoresistance (TMR) in a magnetic tunnel junction consisting of two Fe4GeTe2 layers with the vdW gap acting as an insulating barrier. We predict a TMR ratio of ∼500%, which can be further enhanced by increasing the number of Fe4GeTe2 layers in the junction.
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Affiliation(s)
- Anita Halder
- School
of Physics and CRANN, Trinity College, Dublin 2, Ireland
- Department
of Physics, SRM University − AP, Amaravati 522 502, Andhra Pradesh, India
| | - Declan Nell
- School
of Physics and CRANN, Trinity College, Dublin 2, Ireland
| | - Antik Sihi
- School
of Physics and CRANN, Trinity College, Dublin 2, Ireland
| | - Akash Bajaj
- School
of Physics and CRANN, Trinity College, Dublin 2, Ireland
| | - Stefano Sanvito
- School
of Physics and CRANN, Trinity College, Dublin 2, Ireland
| | - Andrea Droghetti
- School
of Physics and CRANN, Trinity College, Dublin 2, Ireland
- Institute
for Superconducting and Other Innovative Materials for Devices, Italian
National Research Council (CNR-SPIN), G.
D’Annunzio University, Chieti 66100, Italy
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2
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Birch MT, Yasin FS, Litzius K, Powalla L, Wintz S, Schulz F, Kossak AE, Weigand M, Scholz T, Lotsch BV, Schütz G, Yu XZ, Burghard M. Influence of Magnetic Sublattice Ordering on Skyrmion Bubble Stability in 2D Magnet Fe 5GeTe 2. ACS NANO 2024; 18:18246-18256. [PMID: 38975730 PMCID: PMC11256745 DOI: 10.1021/acsnano.4c00853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 06/20/2024] [Accepted: 06/21/2024] [Indexed: 07/09/2024]
Abstract
The realization of above room-temperature ferromagnetism in the two-dimensional (2D) magnet Fe5GeTe2 represents a major advance for the use of van der Waals (vdW) materials in practical spintronic applications. In particular, observations of magnetic skyrmions and related states within exfoliated flakes of this material provide a pathway to the fine-tuning of topological spin textures via 2D material heterostructure engineering. However, there are conflicting reports as to the nature of the magnetic structures in Fe5GeTe2. The matter is further complicated by the study of two types of Fe5GeTe2 crystals with markedly different structural and magnetic properties, distinguished by their specific fabrication procedure: whether they are slowly cooled or rapidly quenched from the growth temperature. In this work, we combine X-ray and electron microscopy to observe the formation of magnetic stripe domains, skyrmion-like type-I, and topologically trivial type-II bubbles, within exfoliated flakes of Fe5GeTe2. The results reveal the influence of the magnetic ordering of the Fe1 sublattice below 150 K, which dramatically alters the magnetocrystalline anisotropy and leads to a complex magnetic phase diagram and a sudden change of the stability of the magnetic textures. In addition, we highlight the significant differences in the magnetic structures intrinsic to slow-cooled and quenched Fe5GeTe2 flakes.
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Affiliation(s)
- Max T. Birch
- Max
Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart 70569, Germany
- RIKEN
Center for Emergent Matter Science, Hirosawa 2-1, Wako 351-0198, Japan
| | - Fehmi S. Yasin
- RIKEN
Center for Emergent Matter Science, Hirosawa 2-1, Wako 351-0198, Japan
- Center
for Nanophase Materials Sciences, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Kai Litzius
- Max
Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart 70569, Germany
| | - Lukas Powalla
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, Stuttgart 70569, Germany
| | - Sebastian Wintz
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, Berlin 14109, Germany
| | - Frank Schulz
- Max
Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart 70569, Germany
| | - Alexander E. Kossak
- Department
of Materials Science and Engineering, Massachusetts
Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Markus Weigand
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, Berlin 14109, Germany
| | - Tanja Scholz
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, Stuttgart 70569, Germany
| | - Bettina V. Lotsch
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, Stuttgart 70569, Germany
- University
of Munich (LMU), Butenandtstraße
5-13 (Haus D), München 81377, Germany
| | - Gisela Schütz
- Max
Planck Institute for Intelligent Systems, Heisenbergstraße 3, Stuttgart 70569, Germany
| | - Xiuzhen Z. Yu
- RIKEN
Center for Emergent Matter Science, Hirosawa 2-1, Wako 351-0198, Japan
| | - Marko Burghard
- Max
Planck Institute for Solid State Research, Heisenbergstraße 1, Stuttgart 70569, Germany
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3
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Yu J, Jin W, Zhang G, Wu H, Xiao B, Yang L, Chang H. Tuning the magnetic properties of van der Waals Fe 3GaTe 2 crystals by Co doping. Phys Chem Chem Phys 2024; 26:18847-18853. [PMID: 38946485 DOI: 10.1039/d4cp01573h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Tuning the magnetic properties of two-dimensional van der Waals ferromagnets has special importance for their practical applications. Using first-principles calculations, we investigate the magnetic properties of Co-doped Fe3GaTe2 with different Co concentrations and different Co atomic sites. Calculation results show that Fe or Co atoms with relatively lower atomic concentrations preferentially occupy Fe1 sites with interlayer coupling, which is more energetically favorable. As the doping concentration of Co atoms increases, the total magnetic moment of the doped system decreases, while the average atomic magnetic moments of Fe1 and Fe2 increase and decrease, respectively, with Fe1 reaching ∼2.08μB. The spin polarization of the doped model 2Co-2 near the Fermi energy level is significantly reduced, while 4Co-3 exhibits an enhanced trend. At some doping level, a phase change from ferromagnetism to antiferromagnetism appears at high Co concentration. These results provide a theoretical basis for experimental studies and valuable information for the development of Fe3GaTe2-based spintronic devices.
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Affiliation(s)
- Jie Yu
- State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Wen Jin
- State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Gaojie Zhang
- State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Hao Wu
- State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Bichen Xiao
- State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Li Yang
- State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Haixin Chang
- State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
- Wuhan National High Magnetic Field Center and Institute for Quantum Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
- Shenzhen R&D Center of Huazhong University of Science and Technology, Shenzhen 518000, China
- Liuzhou Key Laboratory of New Energy Vehicle Power Lithium Battery, School of Electronic Engineering, Guangxi University of Science and Technology, LiuZhou 545006, China
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4
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Mishra S, Park IK, Javaid S, Shin SH, Lee G. Enhancement of interlayer exchange coupling via intercalation in 2D magnetic bilayers: towards high Curie temperature. MATERIALS HORIZONS 2024. [PMID: 38973585 DOI: 10.1039/d4mh00135d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/09/2024]
Abstract
Two-dimensional magnetic materials are considered as promising candidates for developing next-generation spintronic devices by providing the possibility of scaling down to nanometers. However, a low Curie temperature is a crucial problem for practical applications, being intimately related to weak interlayer exchange coupling. Here, by using density functional theory calculations, we show that interlayer exchange coupling can be enhanced by intercalating 3d transition metals (Sc to Zn) into a bilayer of CrI3 and NiI2. It is found that intercalated Ni and Cr atoms exhibit strong antiferromagnetic coupling with the CrI3 and NiI2 host layers, respectively. This enhances the ferromagnetic interlayer exchange coupling between the host layers by many folds compared to pristine CrI3 and NiI2 bilayers. Moreover, both intercalated compounds show out-of-plane magnetic anisotropy with half metallic nature, which makes them ideal candidates for spintronics applications. Thereby our work provides a rational approach to raise the Curie temperature of non-metallic two-dimensional magnets by intercalation.
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Affiliation(s)
- Suman Mishra
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea.
| | - In Kee Park
- Department of Chemistry, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Saqib Javaid
- Department of Chemistry, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
- MMSG, Theoretical Physics Division, PINSTECH, P.O. Nilore, Islamabad, Pakistan
| | - Seung Hwan Shin
- Mutipurpose Synchrotron Radiation Construction Project, Korea Basic Science Institute, 162 Yeongudanji-ro, Cheongwon-gu, Cheongju, Chungcheongbukdo 28119, Republic of Korea.
| | - Geunsik Lee
- Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea.
- Department of Chemistry, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
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5
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Ruiz A, Esteras DL, López-Alcalá D, Baldoví JJ. On the Origin of the Above-Room-Temperature Magnetism in the 2D van der Waals Ferromagnet Fe 3GaTe 2. NANO LETTERS 2024; 24:7886-7894. [PMID: 38842368 PMCID: PMC11229069 DOI: 10.1021/acs.nanolett.4c01019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/31/2024] [Accepted: 05/31/2024] [Indexed: 06/07/2024]
Abstract
2D magnetic materials have attracted growing interest driven by their unique properties and potential applications. However, the scarcity of systems exhibiting magnetism at room temperature has limited their practical implementation into functional devices. Here we focus on the van der Waals ferromagnet Fe3GaTe2, which exhibits above-room-temperature magnetism (Tc = 350-380 K) and strong perpendicular anisotropy. Through first-principles calculations, we examine the magnetic properties of Fe3GaTe2 and compare them with those of Fe3GeTe2. Our calculations unveil the microscopic mechanisms governing their magnetic behavior, emphasizing the pivotal role of ferromagnetic in-plane couplings in the stabilization of the elevated Tc in Fe3GaTe2. Additionally, we predict the stability, substantial perpendicular anisotropy, and high Tc of the single-layer Fe3GaTe2. We also demonstrate the potential of strain engineering and electrostatic doping to modulate its magnetic properties. Our results incentivize the isolation of the monolayer and pave the way for the future optimization of Fe3GaTe2 in magnetic and spintronic nanodevices.
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Affiliation(s)
- Alberto
M. Ruiz
- Instituto
de Ciencia Molecular, Universitat de València, Catedrático José Beltrán
2, 46980 Paterna, Spain
| | - Dorye L. Esteras
- Instituto
de Ciencia Molecular, Universitat de València, Catedrático José Beltrán
2, 46980 Paterna, Spain
| | - Diego López-Alcalá
- Instituto
de Ciencia Molecular, Universitat de València, Catedrático José Beltrán
2, 46980 Paterna, Spain
| | - José J. Baldoví
- Instituto
de Ciencia Molecular, Universitat de València, Catedrático José Beltrán
2, 46980 Paterna, Spain
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6
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Wu X, Mi X, Zhang L, Wang CW, Maraytta N, Zhou X, He M, Merz M, Chai Y, Wang A. Annealing-Tunable Charge Density Wave in the Magnetic Kagome Material FeGe. PHYSICAL REVIEW LETTERS 2024; 132:256501. [PMID: 38996264 DOI: 10.1103/physrevlett.132.256501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 02/13/2024] [Accepted: 05/06/2024] [Indexed: 07/14/2024]
Abstract
The unprecedented phenomenon that a charge density wave (CDW) emerges inside the antiferromagnetic (AFM) phase indicates an unusual CDW mechanism associated with magnetism in FeGe. Here, we demonstrate that both the CDW and magnetism of FeGe can be effectively tuned through postgrowth annealing treatments. Instead of the short-range CDW reported earlier, a long-range CDW order is realized below 110 K in single crystals annealed at 320 °C for over 48 h. The CDW and AFM transition temperatures appear to be inversely correlated with each other. The onset of the CDW phase significantly reduces the critical field of the spin-flop transition, whereas the CDW transition remains stable against minor variations in magnetic orders such as annealing-induced magnetic clusters and spin-canting transitions. Single-crystal x-ray diffraction measurements reveal substantial disorder on the Ge1 site, which is characterized by displacement of the Ge1 atom from the Fe_{3}Ge layer along the c axis and can be reversibly modified by the annealing process. The observed annealing-tunable CDW and magnetic orders can be well understood in terms of disorder on the Ge1 site. Our study provides a vital starting point for the exploration of the unconventional CDW mechanism in FeGe and of kagome materials in general.
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Affiliation(s)
- Xueliang Wu
- Low Temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China
| | - Xinrun Mi
- Low Temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China
| | - Long Zhang
- Low Temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China
| | | | | | | | - Mingquan He
- Low Temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China
| | | | | | - Aifeng Wang
- Low Temperature Physics Laboratory, College of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China
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7
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Yan S, Tian S, Fu Y, Meng F, Li Z, Lei H, Wang S, Zhang X. Highly Efficient Room-Temperature Nonvolatile Magnetic Switching by Current in Fe 3GaTe 2 Thin Flakes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2311430. [PMID: 38444270 DOI: 10.1002/smll.202311430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 12/13/2023] [Indexed: 03/07/2024]
Abstract
Effectively tuning magnetic state by using current is essential for novel spintronic devices. Magnetic van der Waals (vdW) materials have shown superior properties for the applications of magnetic information storage based on the efficient spin torque effect. However, for most of known vdW ferromagnets, the ferromagnetic transition temperatures lower than room temperature strongly impede their applications and the room-temperature vdW spintronic device with low energy consumption is still a long-sought goal. Here, the highly efficient room-temperature nonvolatile magnetic switching is realized by current in a single-material device based on vdW ferromagnet Fe3GaTe2. Moreover, the switching current density and power dissipation are about 300 and 60000 times smaller than conventional spin-orbit-torque devices of magnet/heavy-metal heterostructures. These findings make an important progress on the applications of magnetic vdW materials in the fields of spintronics and magnetic information storage.
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Affiliation(s)
- Shaohua Yan
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Shangjie Tian
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Yang Fu
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Fanyu Meng
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Zhiteng Li
- State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications, Beijing, 100876, China
| | - Hechang Lei
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Shouguo Wang
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Xiao Zhang
- State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications, Beijing, 100876, China
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8
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Yao T, Qubie WL, Kumar P, Bai X, Hu S, Xue D, Zhang J. Critical behaviors of van der Waals itinerant ferromagnet Fe 3.8GaTe 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:345801. [PMID: 38759671 DOI: 10.1088/1361-648x/ad4d48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 05/17/2024] [Indexed: 05/19/2024]
Abstract
The critical behavior of the van der Waals ferromagnet Fe3.8GaTe2was systematically studied through measurements of isothermal magnetization, with the magnetic field applied along thec-axis. Fe3.8GaTe2undergoes a non-continuous paramagnetic to ferromagnetic phase transition at the Curie temperatureTc∼ 355 K. A comprehensive analysis of isotherms aroundTcutilizing the modified Arrott diagram, the Kouvel-Fisher method, the Widom scaling law, and the critical isotherm analysis yielded the critical exponent ofβ= 0.411,γ= 1.246, andδ= 3.99. These critical exponents are found to be self-consistent and align well with the scaling equation at high magnetic fields, underscoring the reliability and intrinsic nature of these parameters. However, the low-field data deviates from the scaling relation, exhibiting a vertical trend whenT
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Affiliation(s)
- Tianyang Yao
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - W L Qubie
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Pushpendra Kumar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Xu Bai
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Shixin Hu
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Desheng Xue
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, People's Republic of China
| | - Junli Zhang
- School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, People's Republic of China
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9
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Zhang C, Jiang Z, Jiang J, He W, Zhang J, Hu F, Zhao S, Yang D, Liu Y, Peng Y, Yang H, Yang H. Above-room-temperature chiral skyrmion lattice and Dzyaloshinskii-Moriya interaction in a van der Waals ferromagnet Fe 3-xGaTe 2. Nat Commun 2024; 15:4472. [PMID: 38796498 PMCID: PMC11127993 DOI: 10.1038/s41467-024-48799-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 05/14/2024] [Indexed: 05/28/2024] Open
Abstract
Skyrmions in existing 2D van der Waals (vdW) materials have primarily been limited to cryogenic temperatures, and the underlying physical mechanism of the Dzyaloshinskii-Moriya interaction (DMI), a crucial ingredient for stabilizing chiral skyrmions, remains inadequately explored. Here, we report the observation of Néel-type skyrmions in a vdW ferromagnet Fe3-xGaTe2 above room temperature. Contrary to previous assumptions of centrosymmetry in Fe3-xGaTe2, the atomic-resolution scanning transmission electron microscopy reveals that the off-centered FeΙΙ atoms break the spatial inversion symmetry, rendering it a polar metal. First-principles calculations further elucidate that the DMI primarily stems from the Te sublayers through the Fert-Lévy mechanism. Remarkably, the chiral skyrmion lattice in Fe3-xGaTe2 can persist up to 330 K at zero magnetic field, demonstrating superior thermal stability compared to other known skyrmion vdW magnets. This work provides valuable insights into skyrmionics and presents promising prospects for 2D material-based skyrmion devices operating beyond room temperature.
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Affiliation(s)
- Chenhui Zhang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Ze Jiang
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Jiawei Jiang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Wa He
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Junwei Zhang
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Fanrui Hu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Shishun Zhao
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Dongsheng Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Yakun Liu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Yong Peng
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China.
| | - Hongxin Yang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
- Center for Quantum Matter, School of Physics, Zhejiang University, Hangzhou, 310058, China.
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore.
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10
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Wang C, Wan S, Wang Y, Shi F, Gong M, Zeng H. Imaging the Magnetic Anisotropy in Ultrathin Fe 4GeTe 2 with a Nitrogen-Vacancy Magnetometer. NANO LETTERS 2024; 24:5754-5760. [PMID: 38708987 DOI: 10.1021/acs.nanolett.4c00795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
Two-dimensional (2D) FenGeTe2, with n = 3, 4, and 5, has been realized in experiments, showing strong magnetic anisotropy with enhanced critical temperature (Tc). The understanding of its magnetic anisotropy is crucial for the exploration of more stable 2D magnets and its spintronic applications. Here, we report a quantitative reconstruction of the magnetization magnitude and its direction in ultrathin Fe4GeTe2 using nitrogen vacancy centers. Through imaging stray magnetic fields, we identified the spin-flop transition at approximately 80 K, resulting in a change of the easy axis from the out-of-plane direction to the in-plane direction. Moreover, by analyzing the thermally activated escape behavior of the magnetization near Tc in terms of the Ginzburg-Landau model, we observed the in-plane magnetic anisotropy effect and the formation capability of magnetic domains at ∼0.4 μm2 μT-1. Our findings contribute to the quantitative understanding of the magnetic anisotropy effect in a vast range of 2D van der Waals magnets.
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Affiliation(s)
- Chen Wang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Science at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- CAS Key Laboratory of Strongly Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, People's Republic of China
| | - Siyuan Wan
- School of Physics and Materials Science, Nanchang University, Nanchang 330031, People's Republic of China
| | - Ya Wang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Science at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- CAS Key Laboratory of Microscale Magnetic Resonance, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, People's Republic of China
| | - Fazhan Shi
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Science at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- CAS Key Laboratory of Microscale Magnetic Resonance, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, People's Republic of China
| | - Ming Gong
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, People's Republic of China
| | - Hualing Zeng
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Science at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- CAS Key Laboratory of Strongly Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, People's Republic of China
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11
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Eguchi R, Sekhar H, Kimura K, Masai H, Happo N, Ikeda M, Yamamoto Y, Utsumi M, Goto H, Takabayashi Y, Tajiri H, Hayashi K, Kubozono Y. Superstructure of Fe 5-xGeTe 2 Determined by Te K-Edge Extended X-ray Absorption Fine Structure and Te Kα X-ray Fluorescence Holography. ACS OMEGA 2024; 9:21287-21297. [PMID: 38764676 PMCID: PMC11097380 DOI: 10.1021/acsomega.4c01395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 04/12/2024] [Accepted: 04/19/2024] [Indexed: 05/21/2024]
Abstract
The local structure of the two-dimensional van der Waals material, Fe5-xGeTe2, which exhibits unique structural/magnetic phase transitions, was investigated by Te K-edge extended X-ray absorption fine structure (EXAFS) and Te Kα X-ray fluorescence holography (XFH) over a wide temperature range. The formation of a trimer of Te atoms at low temperatures has been fully explored using these methods. An increase in the Te-Fe distance at approximately 150 K was suggested by EXAFS and presumably indicates the formation of a Te trimer. Moreover, XFH displayed clear atomic images of Te atoms. Additionally, the distance between the Te atoms shortened, as confirmed from the atomic images reconstructed from XFH, indicating the formation of a trimer of Te atoms, i.e., a charge-ordered superstructure. Furthermore, Te Kα XFH provided unambiguous atomic images of Fe atoms occupying the Fe1 site; the images were not clearly observed in the Ge Kα XFH that was previously reported because of the low occupancy of Fe and Ge atoms. In this study, EXAFS and XFH clearly showed the local structure around the Te atom; in particular, the formation of Te trimers caused by charge-ordered phase transitions was clearly confirmed. The charge-ordered phase transition is fully discussed based on the structural variation at low temperatures, as established from EXAFS and XFH.
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Affiliation(s)
- Ritsuko Eguchi
- Research
Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Halubai Sekhar
- Department
of Physical Science and Technology, Nagoya
Institute of Technology, Nagoya 466-8585, Japan
| | - Koji Kimura
- Department
of Physical Science and Technology, Nagoya
Institute of Technology, Nagoya 466-8585, Japan
- Research
Center for Advanced Measurement and Characterization, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
- Japan
Synchrotron Radiation Research Institute (JASRI), Sayo, Hyogo 679-5198, Japan
| | - Hirokazu Masai
- Department
of Materials and Chemistry, National Institute
of Advanced Industrial Science and Technology (AIST), Osaka 563-8577, Japan
| | - Naohisa Happo
- Graduate
School of Information Sciences, Hiroshima
City University, Hiroshima 731-3194, Japan
| | - Mitsuki Ikeda
- Research
Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Yuki Yamamoto
- Research
Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Masaki Utsumi
- Research
Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Hidenori Goto
- Research
Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Yasuhiro Takabayashi
- Department
of Physical Science and Technology, Nagoya
Institute of Technology, Nagoya 466-8585, Japan
| | - Hiroo Tajiri
- Japan
Synchrotron Radiation Research Institute (JASRI), Sayo, Hyogo 679-5198, Japan
| | - Koichi Hayashi
- Department
of Physical Science and Technology, Nagoya
Institute of Technology, Nagoya 466-8585, Japan
- Japan
Synchrotron Radiation Research Institute (JASRI), Sayo, Hyogo 679-5198, Japan
| | - Yoshihiro Kubozono
- Research
Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
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12
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Liu X, Shan J, Cao T, Zhu L, Ma J, Wang G, Shi Z, Yang Q, Ma M, Liu Z, Yan S, Wang L, Dai Y, Xiong J, Chen F, Wang B, Pan C, Wang Z, Cheng B, He Y, Luo X, Lin J, Liang SJ, Miao F. On-device phase engineering. NATURE MATERIALS 2024:10.1038/s41563-024-01888-y. [PMID: 38664497 DOI: 10.1038/s41563-024-01888-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 04/03/2024] [Indexed: 08/15/2024]
Abstract
In situ tailoring of two-dimensional materials' phases under external stimulus facilitates the manipulation of their properties for electronic, quantum and energy applications. However, current methods are mainly limited to the transitions among phases with unchanged chemical stoichiometry. Here we propose on-device phase engineering that allows us to realize various lattice phases with distinct chemical stoichiometries. Using palladium and selenide as a model system, we show that a PdSe2 channel with prepatterned Pd electrodes can be transformed into Pd17Se15 and Pd4Se by thermally tailoring the chemical composition ratio of the channel. Different phase configurations can be obtained by precisely controlling the thickness and spacing of the electrodes. The device can be thus engineered to implement versatile functions in situ, such as exhibiting superconducting behaviour and achieving ultralow-contact resistance, as well as customizing the synthesis of electrocatalysts. The proposed on-device phase engineering approach exhibits a universal mechanism and can be expanded to 29 element combinations between a metal and chalcogen. Our work highlights on-device phase engineering as a promising research approach through which to exploit fundamental properties as well as their applications.
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Affiliation(s)
- Xiaowei Liu
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Junjie Shan
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Tianjun Cao
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Liang Zhu
- Department of Physics and Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen, China
| | - Jiayu Ma
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-Sen University, Guangzhou, China
| | - Gang Wang
- Department of Physics and Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen, China
| | - Zude Shi
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, China
| | - Qishuo Yang
- Department of Physics and Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen, China
| | - Mingyu Ma
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, China
| | - Zenglin Liu
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Shengnan Yan
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Lizheng Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Yudi Dai
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Junlin Xiong
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Fanqiang Chen
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Buwei Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Chen Pan
- Institute of Interdisciplinary Physical Sciences, School of Physics, Nanjing University of Science and Technology, Nanjing, China
| | - Zhenlin Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Bin Cheng
- Institute of Interdisciplinary Physical Sciences, School of Physics, Nanjing University of Science and Technology, Nanjing, China
| | - Yongmin He
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, China
| | - Xin Luo
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-Sen University, Guangzhou, China.
| | - Junhao Lin
- Department of Physics and Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen, China.
- Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area, Shenzhen, China.
| | - Shi-Jun Liang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China.
| | - Feng Miao
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China.
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13
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Liu S, Hu S, Cui X, Kimura T. Efficient Thermo-Spin Conversion in van der Waals Ferromagnet FeGaTe. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2309776. [PMID: 38127962 DOI: 10.1002/adma.202309776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 12/11/2023] [Indexed: 12/23/2023]
Abstract
Recent discovery of 2D van der Waals magnetic materials has spurred progress in developing advanced spintronic devices. A central challenge lies in enhancing the spin-conversion efficiency for building spin-logic or spin-memory devices. Here, the anomalous Hall and Nernst effects are systematically investigated to uncover significant spin-conversion effects in above-room-temperature van der Waals ferromagnet FeGaTe with perpendicular magnetic anisotropy. The anomalous Hall effect demonstrates an efficient electric spin-charge conversion with a notable spin Hall angle of over 6%. In addition, the anomalous Nernst effect produces a significant transverse voltage at room temperature without a magnetic field, displaying unique temperature dependence with a maximum transverse Seebeck coefficient of 440 nV K-1 and a Nernst angle of ≈62%. Such an innovative thermoelectric signal arises from the efficient thermo-spin conversion effect, where the up-spin and down-spin electrons move in opposite directions under a temperature gradient. The present study highlights the potential of FeGaTe to enhance thermoelectric devices through efficient thermo-spin conversion without the need for a magnetic field.
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Affiliation(s)
- Shuhan Liu
- Department of Physics, Kyushu University, 744 Motooka, Fukuoka, 819-0395, Japan
| | - Shaojie Hu
- Department of Physics, Kyushu University, 744 Motooka, Fukuoka, 819-0395, Japan
| | - Xiaomin Cui
- Department of Physics, Kyushu University, 744 Motooka, Fukuoka, 819-0395, Japan
| | - Takashi Kimura
- Department of Physics, Kyushu University, 744 Motooka, Fukuoka, 819-0395, Japan
- Spintronics Research Network Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
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14
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Wu H, Chen L, Malinowski P, Jang BG, Deng Q, Scott K, Huang J, Ruff JPC, He Y, Chen X, Hu C, Yue Z, Oh JS, Teng X, Guo Y, Klemm M, Shi C, Shi Y, Setty C, Werner T, Hashimoto M, Lu D, Yilmaz T, Vescovo E, Mo SK, Fedorov A, Denlinger JD, Xie Y, Gao B, Kono J, Dai P, Han Y, Xu X, Birgeneau RJ, Zhu JX, da Silva Neto EH, Wu L, Chu JH, Si Q, Yi M. Reversible non-volatile electronic switching in a near-room-temperature van der Waals ferromagnet. Nat Commun 2024; 15:2739. [PMID: 38548765 PMCID: PMC10978849 DOI: 10.1038/s41467-024-46862-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 03/13/2024] [Indexed: 04/01/2024] Open
Abstract
Non-volatile phase-change memory devices utilize local heating to toggle between crystalline and amorphous states with distinct electrical properties. Expanding on this kind of switching to two topologically distinct phases requires controlled non-volatile switching between two crystalline phases with distinct symmetries. Here, we report the observation of reversible and non-volatile switching between two stable and closely related crystal structures, with remarkably distinct electronic structures, in the near-room-temperature van der Waals ferromagnet Fe5-δGeTe2. We show that the switching is enabled by the ordering and disordering of Fe site vacancies that results in distinct crystalline symmetries of the two phases, which can be controlled by a thermal annealing and quenching method. The two phases are distinguished by the presence of topological nodal lines due to the preserved global inversion symmetry in the site-disordered phase, flat bands resulting from quantum destructive interference on a bipartite lattice, and broken inversion symmetry in the site-ordered phase.
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Affiliation(s)
- Han Wu
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
| | - Lei Chen
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
| | - Paul Malinowski
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Bo Gyu Jang
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
- Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Yongin, Republic of Korea
| | - Qinwen Deng
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, USA
| | - Kirsty Scott
- Department of Physics, Yale University, New Haven, CT, USA
- Energy Sciences Institute, Yale University, West Haven, CT, USA
- Department of Physics and Astronomy, University of California, Davis, CA, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
| | - Jianwei Huang
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
| | - Jacob P C Ruff
- Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY, USA
| | - Yu He
- Department of Physics, University of California, Berkeley, CA, USA
| | - Xiang Chen
- Department of Physics, University of California, Berkeley, CA, USA
| | - Chaowei Hu
- Department of Physics, University of Washington, Seattle, WA, USA
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | - Ziqin Yue
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
| | - Ji Seop Oh
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | - Xiaokun Teng
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
| | - Yucheng Guo
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
| | - Mason Klemm
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
| | - Chuqiao Shi
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, USA
| | - Yue Shi
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Chandan Setty
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
| | - Tyler Werner
- Department of Applied Physics, Yale University, New Haven, CT, USA
| | - Makoto Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Donghui Lu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Turgut Yilmaz
- National Synchrotron Light Source II, Brookhaven National Lab, Upton, NY, USA
| | - Elio Vescovo
- National Synchrotron Light Source II, Brookhaven National Lab, Upton, NY, USA
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Alexei Fedorov
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | - Yaofeng Xie
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
| | - Bin Gao
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
| | - Junichiro Kono
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, USA
- Departments of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | - Pengcheng Dai
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
| | - Yimo Han
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, USA
| | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle, WA, USA
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | - Robert J Birgeneau
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Jian-Xin Zhu
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Eduardo H da Silva Neto
- Department of Physics, Yale University, New Haven, CT, USA
- Energy Sciences Institute, Yale University, West Haven, CT, USA
- Department of Physics and Astronomy, University of California, Davis, CA, USA
- Department of Applied Physics, Yale University, New Haven, CT, USA
| | - Liang Wu
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, USA
| | - Jiun-Haw Chu
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Qimiao Si
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA
| | - Ming Yi
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, TX, USA.
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15
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Kajale SN, Nguyen T, Hung NT, Li M, Sarkar D. Field-free deterministic switching of all-van der Waals spin-orbit torque system above room temperature. SCIENCE ADVANCES 2024; 10:eadk8669. [PMID: 38489365 PMCID: PMC10942109 DOI: 10.1126/sciadv.adk8669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 02/08/2024] [Indexed: 03/17/2024]
Abstract
Two-dimensional van der Waals (vdW) magnetic materials hold promise for the development of high-density, energy-efficient spintronic devices for memory and computation. Recent breakthroughs in material discoveries and spin-orbit torque control of vdW ferromagnets have opened a path for integration of vdW magnets in commercial spintronic devices. However, a solution for field-free electric control of perpendicular magnetic anisotropy (PMA) vdW magnets at room temperatures, essential for building compact and thermally stable spintronic devices, is still missing. Here, we report a solution for the field-free, deterministic, and nonvolatile switching of a PMA vdW ferromagnet, Fe3GaTe2, above room temperature (up to 320 K). We use the unconventional out-of-plane anti-damping torque from an adjacent WTe2 layer to enable such switching with a low current density of 2.23 × 106 A cm-2. This study exemplifies the efficacy of low-symmetry vdW materials for spin-orbit torque control of vdW ferromagnets and provides an all-vdW solution for the next generation of scalable and energy-efficient spintronic devices.
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Affiliation(s)
- Shivam N. Kajale
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Thanh Nguyen
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Nguyen Tuan Hung
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Mingda Li
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Deblina Sarkar
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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16
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Zhang KX, Xu H, Keum J, Wang X, Liu M, Chen Z. Unexpected versatile electrical transport behaviors of ferromagnetic nickel films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:235801. [PMID: 38417165 DOI: 10.1088/1361-648x/ad2e25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 02/28/2024] [Indexed: 03/01/2024]
Abstract
Perpendicular magnetic anisotropy (PMA) of magnets is paramount for electrically controlled spintronics due to their intrinsic potentials for higher memory density, scalability, thermal stability and endurance, surpassing an in-plane magnetic anisotropy (IMA). Nickel film is a long-lived fundamental element ferromagnet, yet its electrical transport behavior associated with magnetism has not been comprehensively studied, hindering corresponding spintronic applications exploiting nickel-based compounds. Here, we systematically investigate the highly versatile magnetism and corresponding transport behavior of nickel films. As the thickness reduces within the general thickness regime of a magnet layer for a memory device, the hardness of nickel films' ferromagnetic loop of anomalous Hall effect increases and then decreases, reflecting the magnetic transitions from IMA to PMA and back to IMA. Additionally, the square ferromagnetic loop changes from a hard to a soft one at rising temperatures, indicating a shift from PMA to IMA. Furthermore, we observe a butterfly magnetoresistance resulting from the anisotropic magnetoresistance effect, which evolves in conjunction with the thickness and temperature-dependent magnetic transformations as a complementary support. Our findings unveil the rich magnetic dynamics and most importantly settle down the most useful guiding information for current-driven spintronic applications based on nickel film: The hysteresis loop is squarest for the ∼8 nm-thick nickel film, of highest hardness withRxyr/Rxys∼ 1 and minimumHs-Hc, up to 125 K; otherwise, extra care should be taken for a different thickness or at a higher temperature.
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Affiliation(s)
- Kai-Xuan Zhang
- Center for Quantum Materials, Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea
| | - Hanshu Xu
- Department of Applied Physics, School of Biomedical Engineering, Anhui Medical University, Hefei 230032, People's Republic of China
| | - Jihoon Keum
- Center for Quantum Materials, Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea
| | - Xiangqi Wang
- Jihua Laboratory Testing Center, Jihua Laboratory, Foshan 528000, People's Republic of China
| | - Meizhuang Liu
- School of Semiconductor Science and Technology, South China Normal University, Foshan 528225, People's Republic of China
| | - Zuxin Chen
- School of Semiconductor Science and Technology, South China Normal University, Foshan 528225, People's Republic of China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou 510631, People's Republic of China
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17
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Zhang H, Chen X, Wang T, Huang X, Chen X, Shao YT, Meng F, Meisenheimer P, N'Diaye A, Klewe C, Shafer P, Pan H, Jia Y, Crommie MF, Martin LW, Yao J, Qiu Z, Muller DA, Birgeneau RJ, Ramesh R. Room-Temperature, Current-Induced Magnetization Self-Switching in A Van Der Waals Ferromagnet. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2308555. [PMID: 38016700 DOI: 10.1002/adma.202308555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/30/2023] [Indexed: 11/30/2023]
Abstract
2D layered materials with broken inversion symmetry are being extensively pursued as spin source layers to realize high-efficiency magnetic switching. Such low-symmetry layered systems are, however, scarce. In addition, most layered magnets with perpendicular magnetic anisotropy show a low Curie temperature. Here, the experimental observation of spin-orbit torque magnetization self-switching at room temperature in a layered polar ferromagnetic metal, Fe2.5 Co2.5 GeTe2 is reported. The spin-orbit torque is generated from the broken inversion symmetry along the c-axis of the crystal. These results provide a direct pathway toward applicable 2D spintronic devices.
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Affiliation(s)
- Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Tianye Wang
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Xianzhe Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Yu-Tsun Shao
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, 90089, USA
| | - Fanhao Meng
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Peter Meisenheimer
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Alpha N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Christoph Klewe
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Hao Pan
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Yanli Jia
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Michael F Crommie
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Departments of Materials Science and NanoEngineering, Chemistry, and Physics and Astronomy, Rice University, Houston, TX, 77005, USA
- Rice Advanced Materials Institute, Rice University, Houston, TX, 77005, USA
| | - Jie Yao
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ziqiang Qiu
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, 14853, USA
| | - Robert J Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California, Berkeley, CA, 94720, USA
- Department of Physics and Astronomy, Department of Materials Science and Nanoengineering, Rice University, Houston, TX, 77005, USA
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18
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Kajale SN, Nguyen T, Chao CA, Bono DC, Boonkird A, Li M, Sarkar D. Current-induced switching of a van der Waals ferromagnet at room temperature. Nat Commun 2024; 15:1485. [PMID: 38374025 PMCID: PMC10876566 DOI: 10.1038/s41467-024-45586-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 01/30/2024] [Indexed: 02/21/2024] Open
Abstract
Recent discovery of emergent magnetism in van der Waals magnetic materials (vdWMM) has broadened the material space for developing spintronic devices for energy-efficient computation. While there has been appreciable progress in vdWMM discovery, a solution for non-volatile, deterministic switching of vdWMMs at room temperature has been missing, limiting the prospects of their adoption into commercial spintronic devices. Here, we report the first demonstration of current-controlled non-volatile, deterministic magnetization switching in a vdW magnetic material at room temperature. We have achieved spin-orbit torque (SOT) switching of the PMA vdW ferromagnet Fe3GaTe2 using a Pt spin-Hall layer up to 320 K, with a threshold switching current density as low as [Formula: see text]1.69 [Formula: see text] 106 A cm-2 at room temperature. We have also quantitatively estimated the anti-damping-like SOT efficiency of our Fe3GaTe2/Pt bilayer system to be [Formula: see text], using the second harmonic Hall voltage measurement technique. These results mark a crucial step in making vdW magnetic materials a viable choice for the development of scalable, energy-efficient spintronic devices.
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Affiliation(s)
- Shivam N Kajale
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Thanh Nguyen
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Corson A Chao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - David C Bono
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Artittaya Boonkird
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mingda Li
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Deblina Sarkar
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, USA.
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19
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Ngaloy R, Zhao B, Ershadrad S, Gupta R, Davoudiniya M, Bainsla L, Sjöström L, Hoque MA, Kalaboukhov A, Svedlindh P, Sanyal B, Dash SP. Strong In-Plane Magnetization and Spin Polarization in (Co 0.15Fe 0.85) 5GeTe 2/Graphene van der Waals Heterostructure Spin-Valve at Room Temperature. ACS NANO 2024. [PMID: 38330915 PMCID: PMC10883121 DOI: 10.1021/acsnano.3c07462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Van der Waals (vdW) magnets are promising, because of their tunable magnetic properties with doping or alloy composition, where the strength of magnetic interactions, their symmetry, and magnetic anisotropy can be tuned according to the desired application. However, so far, most of the vdW magnet-based spintronic devices have been limited to cryogenic temperatures with magnetic anisotropies favoring out-of-plane or canted orientation of the magnetization. Here, we report beyond room-temperature lateral spin-valve devices with strong in-plane magnetization and spin polarization of the vdW ferromagnet (Co0.15Fe0.85)5GeTe2 (CFGT) in heterostructures with graphene. Density functional theory (DFT) calculations show that the magnitude of the anisotropy depends on the Co concentration and is caused by the substitution of Co in the outermost Fe layer. Magnetization measurements reveal the above room-temperature ferromagnetism in CFGT and clear remanence at room temperature. Heterostructures consisting of CFGT nanolayers and graphene were used to experimentally realize basic building blocks for spin valve devices, such as efficient spin injection and detection. Further analysis of spin transport and Hanle spin precession measurements reveals a strong in-plane magnetization with negative spin polarization at the interface with graphene, which is supported by the calculated spin-polarized density of states of CFGT. The in-plane magnetization of CFGT at room temperature proves its usefulness in graphene lateral spin-valve devices, thus revealing its potential application in spintronic technologies.
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Affiliation(s)
- Roselle Ngaloy
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Bing Zhao
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Soheil Ershadrad
- Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala, Sweden
| | - Rahul Gupta
- Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala, Sweden
- Department of Materials Science and Engineering, Uppsala University, Box 35, SE-751 03 Uppsala, Sweden
| | - Masoumeh Davoudiniya
- Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala, Sweden
| | - Lakhan Bainsla
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
- Department of Physics, Indian Institute of Technology Ropar, Roopnagar 140001, Punjab, India
| | - Lars Sjöström
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Md Anamul Hoque
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Alexei Kalaboukhov
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Peter Svedlindh
- Department of Materials Science and Engineering, Uppsala University, Box 35, SE-751 03 Uppsala, Sweden
| | - Biplab Sanyal
- Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala, Sweden
| | - Saroj Prasad Dash
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
- Graphene Center, Chalmers University of Technology, SE-41296 Göteborg, Sweden
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20
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De Vita A, Sant R, Polewczyk V, van der Laan G, Brookes NB, Kong T, Cava RJ, Rossi G, Vinai G, Panaccione G. Evidence of Temperature-Dependent Interplay between Spin and Orbital Moment in van der Waals Ferromagnet VI 3. NANO LETTERS 2024; 24:1487-1493. [PMID: 38285518 DOI: 10.1021/acs.nanolett.3c03525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2024]
Abstract
van der Waals materials provide a versatile toolbox for the emergence of new quantum phenomena and fabrication of functional heterostructures. Among them, the trihalide VI3 stands out for its unique magnetic and structural landscape. Here we investigate the spin and orbital magnetic degrees of freedom in the layered ferromagnet VI3 by means of temperature-dependent X-ray absorption spectroscopy and X-ray magnetic circular and linear dichroism. We detect localized electronic states and reduced magnetic dimensionality, due to electronic correlations. We furthermore provide experimental evidence of (a) an unquenched orbital magnetic moment (up to 0.66(7) μB/V atom) in the ferromagnetic state and (b) an instability of the orbital moment in the proximity of the spin reorientation transition. Our results support a coherent picture where electronic correlations give rise to a strong magnetic anisotropy and a large orbital moment and establish VI3 as a prime candidate for the study of orbital quantum effects.
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Affiliation(s)
- Alessandro De Vita
- Dipartimento di Fisica, Universitá degli Studi di Milano, Via Celoria 16, I-20133 Milano, Italy
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, km 163.5, I-34149 Trieste, Italy
| | - Roberto Sant
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, CS40220, 38043 Grenoble Cedex 9, France
| | - Vincent Polewczyk
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, km 163.5, I-34149 Trieste, Italy
| | - Gerrit van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K
| | - Nicholas B Brookes
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, CS40220, 38043 Grenoble Cedex 9, France
| | - Tai Kong
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
| | - Robert J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
| | - Giorgio Rossi
- Dipartimento di Fisica, Universitá degli Studi di Milano, Via Celoria 16, I-20133 Milano, Italy
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, km 163.5, I-34149 Trieste, Italy
| | - Giovanni Vinai
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, km 163.5, I-34149 Trieste, Italy
| | - Giancarlo Panaccione
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, km 163.5, I-34149 Trieste, Italy
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21
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Moon A, Li Y, McKeever C, Casas BW, Bravo M, Zheng W, Macy J, Petford-Long AK, McCandless GT, Chan JY, Phatak C, Santos EJG, Balicas L. Writing and Detecting Topological Charges in Exfoliated Fe 5-xGeTe 2. ACS NANO 2024; 18:4216-4228. [PMID: 38262067 DOI: 10.1021/acsnano.3c09234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Fe5-xGeTe2 is a promising two-dimensional (2D) van der Waals (vdW) magnet for practical applications, given its magnetic properties. These include Curie temperatures above room temperature, and topological spin textures─TST (both merons and skyrmions), responsible for a pronounced anomalous Hall effect (AHE) and its topological counterpart (THE), which can be harvested for spintronics. Here, we show that both the AHE and THE can be amplified considerably by just adjusting the thickness of exfoliated Fe5-xGeTe2, with THE becoming observable even in zero magnetic field due to a field-induced unbalance in topological charges. Using a complementary suite of techniques, including electronic transport, Lorentz transmission electron microscopy, and micromagnetic simulations, we reveal the emergence of substantial coercive fields upon exfoliation, which are absent in the bulk, implying thickness-dependent magnetic interactions that affect the TST. We detected a "magic" thickness t ≈ 30 nm where the formation of TST is maximized, inducing large magnitudes for the topological charge density (∼6.45 × 1020 cm-2), and the concomitant anomalous (ρxyA,max ≃22.6 μΩ cm) and topological (ρxyu,T 1≃5 μΩ cm) Hall resistivities at T ≈ 120 K. These values for ρxyA,max and ρxyu,T are higher than those found in magnetic topological insulators and, so far, the largest reported for 2D magnets. The hitherto unobserved THE under zero magnetic field could provide a platform for the writing and electrical detection of TST aiming at energy-efficient devices based on vdW ferromagnets.
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Affiliation(s)
- Alex Moon
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, Florida 32310, United States
- Department of Physics, Florida State University, 77 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Yue Li
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Conor McKeever
- Institute for Condensed Matter and Complex Systems, School of Physics and Astronomy, The University of Edinburgh, Edinburgh EH9 3FD, U.K
| | - Brian W Casas
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, Florida 32310, United States
| | - Moises Bravo
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Wenkai Zheng
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, Florida 32310, United States
- Department of Physics, Florida State University, 77 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Juan Macy
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, Florida 32310, United States
- Department of Physics, Florida State University, 77 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Amanda K Petford-Long
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Gregory T McCandless
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Julia Y Chan
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Charudatta Phatak
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Elton J G Santos
- Institute for Condensed Matter and Complex Systems, School of Physics and Astronomy, The University of Edinburgh, Edinburgh EH9 3FD, U.K
- Higgs Centre for Theoretical Physics, The University of Edinburgh, Edinburgh EH9 3FD, U.K
| | - Luis Balicas
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, Florida 32310, United States
- Department of Physics, Florida State University, 77 Chieftan Way, Tallahassee, Florida 32306, United States
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22
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An Z, Lv L, Su Y, Jiang Y, Guan Z. Carrier doping modulates the magnetoelectronic and magnetic anisotropic properties of two-dimensional MSi 2N 4 (M = Cr, Mn, Fe, and Co) monolayers. Phys Chem Chem Phys 2024; 26:4208-4217. [PMID: 38230688 DOI: 10.1039/d3cp05032g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Through extensive density functional theory (DFT) calculations, our investigation delves into the stability, electrical characteristics, and magnetic behavior of monolayers (MLs) of MSi2N4. Computational analyses indicate intrinsic antiferromagnetic (AFM) orders within the MSi2N4 MLs, as a result of direct exchange interactions among transition metal (M) atoms. We further find that CrSi2N4 and CoSi2N4 MLs with primitive cells (pcells) exhibit half-metallic properties, with respective spin-β electron gaps of 3.661 and 2.021 eV. In contrast, MnSi2N4 and FeSi2N4 MLs with pcells act as semiconductors, having energy gaps of 0.427 and 0.282 eV, respectively. When the SOC is considered, the CrSi2N4, MnSi2N4 and FeSi2N4 MLs are metals, while the CoSi2N4 ML is a semiconductor. Our findings imply the dynamics and thermodynamic stability of MSi2N4 MLs. We have also explored the influence of carrier doping on the electromagnetic attributes of MSi2N4 MLs. Interestingly, charge doping could transform CrSi2N4, MnSi2N4, and CoSi2N4 MLs from their original AFM state into a ferromagnetic (FM) order. Moreover, carrier doping transformed CrSi2N4 and CoSi2N4 MLs from spin-polarized metals to half-metals (HMs). It is of particular note that doping of CrSi2N4 MLs with +0.9 e per pcell or more holes caused a switch in the easy axis (EA) to the [001] axis. The demonstrated intrinsic AFM order, excellent thermodynamic and kinetic stability, adjustable magnetism, and half-metallicity of the MSi2N4 family suggest its promising potential for applications in the realm of spintronics.
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Affiliation(s)
- Ziyuan An
- Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, P. R. China.
| | - Linhui Lv
- Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, P. R. China.
| | - Ya Su
- School of Electrical Engineering, Shandong University, Jinan, Shandong 250100, P. R. China.
| | - Yanyan Jiang
- Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials (Ministry of Education), School of Materials Science and Engineering, Shandong University, Jinan, Shandong, 250061, P. R. China
| | - Zhaoyong Guan
- Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, P. R. China.
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P. R. China
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23
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Yan S, He HH, Fu Y, Zhao NN, Tian S, Yin Q, Meng F, Cao X, Wang L, Chen S, Son KH, Choi JW, Ryu H, Wang S, Lei H, Liu K, Zhang X. Near-room temperature ferromagnetism and a tunable anomalous Hall effect in atomically thin Fe 4CoGeTe 2. NANOSCALE 2024; 16:1406-1414. [PMID: 38165953 DOI: 10.1039/d3nr03594h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Itinerant ferromagnetism at room temperature is a key factor for spin transport and manipulation. Here, we report the realization of near-room temperature itinerant ferromagnetism in Co doped Fe5GeTe2 thin flakes. The ferromagnetic transition temperature TC (∼323 K-337 K) is almost unchanged when the thickness is as low as 12 nm and is still about 284 K at 2 nm (bilayer thickness). Theoretical calculations further indicate that the ferromagnetism persists in monolayer Fe4CoGeTe2. In addition to the robust ferromagnetism down to the ultrathin limit, Fe4CoGeTe2 exhibits an unusual temperature- and thickness-dependent intrinsic anomalous Hall effect. We propose that it could be ascribed to the dependence of the band structure on thickness that changes the Berry curvature near the Fermi energy level subtly. The near-room temperature ferromagnetism and tunable anomalous Hall effect in atomically thin Fe4CoGeTe2 provide opportunities to understand the exotic transport properties of two-dimensional van der Waals magnetic materials and explore their potential applications in spintronics.
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Affiliation(s)
- Shaohua Yan
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Hui-Hui He
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Yang Fu
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Ning-Ning Zhao
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Shangjie Tian
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei 230601, China
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Qiangwei Yin
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Fanyu Meng
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Xinyu Cao
- State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China.
| | - Le Wang
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Shanshan Chen
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Ki-Hoon Son
- Center for Spintronics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Jun Woo Choi
- Center for Spintronics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Hyejin Ryu
- Center for Spintronics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Shouguo Wang
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei 230601, China
| | - Hechang Lei
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Kai Liu
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing 100872, China.
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, China
| | - Xiao Zhang
- State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China.
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24
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Eguchi R, Ikeda M, Yamamoto Y, Goto H, Happo N, Kimura K, Hayashi K, Kubozono Y. Observation of the Superstructure in Fe 5-xGeTe 2 by X-ray Fluorescence Holography. Inorg Chem 2024; 63:947-953. [PMID: 38157480 DOI: 10.1021/acs.inorgchem.3c02254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Fe5-xGeTe2 is a two-dimensional van der Waals material that exhibits ferromagnetic order with a high Curie temperature (TC) of around room temperature. In addition to TC, two magnetic transitions occur with decreasing temperature, and a charge-ordered state is observed at low temperatures. We employed Ge Kα X-ray fluorescence holography (XFH) for Fe5-xGeTe2 to directly investigate the local structure in the charge-ordered state, i.e., the 3 × 3 superstructure. The Ge Kα XFH results revealed local atomic structures around the Ge atom, thus clarifying the simultaneous locations and arrangements of the Te, Fe, and Ge atoms. The atomic positions relative to the Ge atom are useful for understanding the coexistence of the ideal 1 × 1 structure and 3 × 3 superstructure found in the charge-ordered state.
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Affiliation(s)
- Ritsuko Eguchi
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Mitsuki Ikeda
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Yuki Yamamoto
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Hidenori Goto
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Naohisa Happo
- Graduate School of Information Sciences, Hiroshima City University, Hiroshima 731-3194, Japan
| | - Koji Kimura
- Department of Physical Science and Technology, Nagoya Institute of Technology, Nagoya 466-8585, Japan
- Research Center for Advanced Measurement and Characterization, National Institute for Materials Science, Tsukuba 305-0047, Japan
| | - Koichi Hayashi
- Department of Physical Science and Technology, Nagoya Institute of Technology, Nagoya 466-8585, Japan
| | - Yoshihiro Kubozono
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
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25
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Miao W, Zhen W, Tan C, Wang J, Nie Y, Wang H, Wang L, Niu Q, Tian M. Nonreciprocal Antisymmetric Magnetoresistance and Unconventional Hall Effect in a Two-Dimensional Ferromagnet. ACS NANO 2023; 17:25449-25458. [PMID: 38051216 DOI: 10.1021/acsnano.3c08954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Two-dimensional (2D) ferromagnets with high Curie temperatures provide a rich platform for exploring the exotic phenomena of 2D magnetism and the potential of spintronic devices. As a prototypical 2D ferromagnet, Fe5-xGeTe2 has recently been reported to possess a high Curie temperature with Tc ∼ 310 K, making it a promising candidate for advancing 2D nanoelectromechanical systems. However, due to its intricate magnetic ground state and magnetic domains, a thorough study of the transport behavior related to its lattice and domain structures is still lacking. Here, we report a nonreciprocal antisymmetric magnetoresistance in Fe5-xGeTe2 nanoflakes observed under an external magnetic field between 85-120 K. Through a detailed examination of its temperature, field orientation, and sample thickness dependence, we trace its origin to an additional electric field induced by the domain structure. This differs from the previously reported antisymmetric magnetoresistance due to thickness inhomogeneity. Notably, at lower temperatures, we observed an unconventional Hall effect (UHE), which can be attributed to the Dzyaloshinskii-Moriya interaction (DMI) resulting from the non-coplanar magnetic moment structure. The pronounced influence of sample thickness on magneto-transport properties underscores the competition between magnetic anisotropy and DMI in Fe5-xGeTe2 flakes with varying thicknesses. Our findings provide a deeper understanding of the magneto-transport behavior of the exotic magnetic structure in 2D ferromagnetic materials, which may benefit future spintronic device applications.
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Affiliation(s)
- Weiting Miao
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
- Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Weili Zhen
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Cheng Tan
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), School of Science, RMIT University, Melbourne, VIC 3001, Australia
| | - Jie Wang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Yong Nie
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Hengning Wang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Lan Wang
- Lab of Low Dimensional Magnetism and Spintronic Devices, School of Physics, Hefei University of Technology, Hefei 230009, Anhui, China
| | - Qun Niu
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Mingliang Tian
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei 230601, Anhui, China
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26
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Tian S, Wang W, Zhao M, Han Y, Tian Y, Ji S, Yao L, Liu L, Ling F, Jia Z, Zhang F. Room-temperature ferromagnetic CoSe 2nanoplates synthesized by chemical vapor deposition. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 36:135802. [PMID: 38064749 DOI: 10.1088/1361-648x/ad13d5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023]
Abstract
Among novel two-dimensional materials, transition metal dichalcogenides (TMDs) with 3dmagnetic elements have been extensively researched owing to their unique magnetic, electric, and photoelectric properties. As an important member of TMDs, CoSe2is an interesting material with controversial magnetic properties, hitherto there are few reports related to the magnetism of CoSe2materials. Here, we report the synthesis of CoSe2nanoplates on Al2O3substrates by chemical vapor deposition (CVD). The CVD-grown CoSe2nanoplates exhibit three typical morphologies (regular hexagonal, hexagonal, and pentagonal shapes) and their lateral sizes and thickness of CoSe2nanoplates can reach up to hundreds of microns and several hundred nanometers, respectively. The electric-transport measurement shows a metallic feature of CoSe2nanoplates. Furthermore, the slanted hysteresis loop and nonzero remnant magnetization of the CoSe2nanoplates confirm the ferromagnetism in the temperature range of 5-400 K. This work provides a novel platform for designing CoSe2-based spintronic devices and studying related magnetic mechanisms.
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Affiliation(s)
- Sen Tian
- Institute of Quantum Materials and Devices, Tiangong University, Tianjin 300387, People's Republic of China
| | - Wenjie Wang
- College of Science, China Agricultural University, Beijing 100083, People's Republic of China
| | - Mengfan Zhao
- Institute of Quantum Materials and Devices, Tiangong University, Tianjin 300387, People's Republic of China
| | - Yilin Han
- Institute of Quantum Materials and Devices, Tiangong University, Tianjin 300387, People's Republic of China
| | - Yuxin Tian
- Institute of Quantum Materials and Devices, Tiangong University, Tianjin 300387, People's Republic of China
| | - Shengxiang Ji
- Institute of Quantum Materials and Devices, Tiangong University, Tianjin 300387, People's Republic of China
| | - Liang Yao
- Institute of Quantum Materials and Devices, Tiangong University, Tianjin 300387, People's Republic of China
| | - Lixuan Liu
- Institute of Quantum Materials and Devices, Tiangong University, Tianjin 300387, People's Republic of China
| | - Feifei Ling
- Hebei Technology Innovation Center of Phase Change Thermal Management of Data Center, Hebei University of Water Resources and Electric Engineering, Cangzhou 061001, People's Republic of China
| | - Zhiyan Jia
- Institute of Quantum Materials and Devices, Tiangong University, Tianjin 300387, People's Republic of China
| | - Fang Zhang
- Institute of Quantum Materials and Devices, Tiangong University, Tianjin 300387, People's Republic of China
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27
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Ren H, Lan M. Progress and Prospects in Metallic Fe xGeTe 2 (3 ≤ x ≤ 7) Ferromagnets. Molecules 2023; 28:7244. [PMID: 37959664 PMCID: PMC10649090 DOI: 10.3390/molecules28217244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/05/2023] [Accepted: 10/21/2023] [Indexed: 11/15/2023] Open
Abstract
Thermal fluctuations in two-dimensional (2D) isotropy systems at non-zero finite temperatures can destroy the long-range (LR) magnetic order due to the mechanisms addressed in the Mermin-Wanger theory. However, the magnetic anisotropy related to spin-orbit coupling (SOC) may stabilize magnetic order in 2D systems. Very recently, 2D FexGeTe2 (3 ≤ x ≤ 7) with a high Curie temperature (TC) has not only undergone significant developments in terms of synthetic methods and the control of ferromagnetism (FM), but is also being actively explored for applications in various devices. In this review, we introduce six experimental methods, ten ferromagnetic modulation strategies, and four spintronic devices for 2D FexGeTe2 materials. In summary, we outline the challenges and potential research directions in this field.
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Affiliation(s)
- Hongtao Ren
- School of Materials Science and Engineering, Liaocheng University, Liaocheng 252000, China
| | - Mu Lan
- College of Optoelectronic Engineering, Chengdu University of Information Technology, Chengdu 610225, China
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28
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Liu P, Zhang Y, Li K, Li Y, Pu Y. Recent advances in 2D van der Waals magnets: Detection, modulation, and applications. iScience 2023; 26:107584. [PMID: 37664598 PMCID: PMC10470320 DOI: 10.1016/j.isci.2023.107584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023] Open
Abstract
The emergence of two-dimensional (2D) van der Waals magnets provides an exciting platform for exploring magnetism in the monolayer limit. Exotic quantum phenomena and significant potential for spintronic applications are demonstrated in 2D magnetic crystals and heterostructures, which offer unprecedented possibilities in advanced formation technology with low power and high efficiency. In this review, we summarize recent advances in 2D van der Waals magnetic crystals. We focus mainly on van der Waals materials of truly 2D nature with intrinsic magnetism. The detection methods of 2D magnetic materials are first introduced in detail. Subsequently, the effective strategies to modulate the magnetic behavior of 2D magnets (e.g., Curie temperature, magnetic anisotropy, magnetic exchange interaction) are presented. Then, we list the applications of 2D magnets in the spintronic devices. We also highlight current challenges and broad space for the development of 2D magnets in further studies.
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Affiliation(s)
- Ping Liu
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Ying Zhang
- Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, University of Science and Technology of China, Hefei 230026, China
| | - Kehan Li
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Yongde Li
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Yong Pu
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
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29
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Lv H, da Silva A, Figueroa AI, Guillemard C, Aguirre IF, Camosi L, Aballe L, Valvidares M, Valenzuela SO, Schubert J, Schmidbauer M, Herfort J, Hanke M, Trampert A, Engel-Herbert R, Ramsteiner M, Lopes JMJ. Large-Area Synthesis of Ferromagnetic Fe 5- x GeTe 2 /Graphene van der Waals Heterostructures with Curie Temperature above Room Temperature. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2302387. [PMID: 37231567 DOI: 10.1002/smll.202302387] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/10/2023] [Indexed: 05/27/2023]
Abstract
Van der Waals (vdW) heterostructures combining layered ferromagnets and other 2D crystals are promising building blocks for the realization of ultracompact devices with integrated magnetic, electronic, and optical functionalities. Their implementation in various technologies depends strongly on the development of a bottom-up scalable synthesis approach allowing for realizing highly uniform heterostructures with well-defined interfaces between different 2D-layered materials. It is also required that each material component of the heterostructure remains functional, which ideally includes ferromagnetic order above room temperature for 2D ferromagnets. Here, it is demonstrated that the large-area growth of Fe5- x GeTe2 /graphene heterostructures is achieved by vdW epitaxy of Fe5- x GeTe2 on epitaxial graphene. Structural characterization confirms the realization of a continuous vdW heterostructure film with a sharp interface between Fe5- x GeTe2 and graphene. Magnetic and transport studies reveal that the ferromagnetic order persists well above 300 K with a perpendicular magnetic anisotropy. In addition, epitaxial graphene on SiC(0001) continues to exhibit a high electronic quality. These results represent an important advance beyond nonscalable flake exfoliation and stacking methods, thus marking a crucial step toward the implementation of ferromagnetic 2D materials in practical applications.
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Affiliation(s)
- Hua Lv
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Alessandra da Silva
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Adriana I Figueroa
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
| | - Charles Guillemard
- ALBA Synchrotron Light Source, Cerdanyola del Valles, Barcelona, 08290, Spain
| | - Iván Fernández Aguirre
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
- Universitat Autònoma de Barcelona, Bellaterra, Barcelona, 08193, Spain
| | - Lorenzo Camosi
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
| | - Lucia Aballe
- ALBA Synchrotron Light Source, Cerdanyola del Valles, Barcelona, 08290, Spain
| | - Manuel Valvidares
- ALBA Synchrotron Light Source, Cerdanyola del Valles, Barcelona, 08290, Spain
| | - Sergio O Valenzuela
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, 08010, Spain
| | - Jürgen Schubert
- Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich, 52425, Jülich, Germany
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, 52425, Jülich, Germany
| | | | - Jens Herfort
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Michael Hanke
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Achim Trampert
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Roman Engel-Herbert
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Manfred Ramsteiner
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Joao Marcelo J Lopes
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
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30
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Ren H, Xiang G. Strain Engineering of Intrinsic Ferromagnetism in 2D van der Waals Materials. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2378. [PMID: 37630963 PMCID: PMC10459406 DOI: 10.3390/nano13162378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 08/09/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023]
Abstract
Since the discovery of the low-temperature, long-range ferromagnetic order in monolayers Cr2Ge2Te6 and CrI3, many efforts have been made to achieve a room temperature (RT) ferromagnet. The outstanding deformation ability of two-dimensional (2D) materials provides an exciting way to mediate their intrinsic ferromagnetism (FM) with strain engineering. Here, we summarize the recent progress of strain engineering of intrinsic FM in 2D van der Waals materials. First, we introduce how to explain the strain-mediated intrinsic FM on Cr-based and Fe-based 2D van der Waals materials through ab initio Density functional theory (DFT), and how to calculate magnetic anisotropy energy (MAE) and Curie temperature (TC) from the interlayer exchange coupling J. Subsequently, we focus on numerous attempts to apply strain to 2D materials in experiments, including wrinkle-induced strain, flexible substrate bending or stretching, lattice mismatch, electrostatic force and field-cooling. Last, we emphasize that this field is still in early stages, and there are many challenges that need to be overcome. More importantly, strengthening the guideline of strain-mediated FM in 2D van der Waals materials will promote the development of spintronics and straintronics.
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Affiliation(s)
- Hongtao Ren
- School of Materials Science and Engineering, Liaocheng University, Hunan Road No. 1, Liaocheng 252000, China
| | - Gang Xiang
- College of Physics, Sichuan University, Wangjiang Road No. 29, Chengdu 610064, China
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31
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Wang H, Wen Y, Zeng H, Xiong Z, Tu Y, Zhu H, Cheng R, Yin L, Jiang J, Zhai B, Liu C, Shan C, He J. 2D Ferroic Materials for Nonvolatile Memory Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2305044. [PMID: 37486859 DOI: 10.1002/adma.202305044] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 07/21/2023] [Indexed: 07/26/2023]
Abstract
The emerging nonvolatile memory technologies based on ferroic materials are promising for producing high-speed, low-power, and high-density memory in the field of integrated circuits. Long-range ferroic orders observed in 2D materials have triggered extensive research interest in 2D magnets, 2D ferroelectrics, 2D multiferroics, and their device applications. Devices based on 2D ferroic materials and heterostructures with an atomically smooth interface and ultrathin thickness have exhibited impressive properties and significant potential for developing advanced nonvolatile memory. In this context, a systematic review of emergent 2D ferroic materials is conducted here, emphasizing their recent research on nonvolatile memory applications, with a view to proposing brighter prospects for 2D magnetic materials, 2D ferroelectric materials, 2D multiferroic materials, and their relevant devices.
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Affiliation(s)
- Hao Wang
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Yao Wen
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Hui Zeng
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Ziren Xiong
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Yangyuan Tu
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Hao Zhu
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Ruiqing Cheng
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Lei Yin
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Jian Jiang
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Baoxing Zhai
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Chuansheng Liu
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Chongxin Shan
- Henan Key Laboratory of Diamond Optoelectronic Materials and Devices, Key Laboratory of Material Physics, Ministry of Education, School of Physics, Zhengzhou University, Zhengzhou, 450052, China
| | - Jun He
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, 430072, China
- Hubei Luojia Laboratory, Wuhan, 430079, China
- Wuhan Institute of Quantum Technology, Wuhan, 430206, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100190, China
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32
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Ahn HB, Jung SG, Lim H, Kim K, Kim S, Park TE, Park T, Lee C. Giant coercivity enhancement in a room-temperature van der Waals magnet through substitutional metal-doping. NANOSCALE 2023. [PMID: 37357947 DOI: 10.1039/d3nr00681f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
Abstract
FexGeTe2 (x = 3, 4, and 5) systems, two-dimensional (2D) van der Waals (vdW) ferromagnetic (FM) metals with high Curie temperatures (TC), have been intensively studied to realize all-2D spintronic devices. Recently, an intrinsic FM material Fe3GaTe2 with high TC (350-380 K) has been reported. As substitutional doping changes the magnetic properties of vdW magnets, it can be a powerful means for engineering the properties of magnetic materials. Here, the coercive field (Hc) is substantially enhanced by substituting Ni for Fe in (Fe1-xNix)3GaTe2 crystals. The introduction of a Ni dopant with x = 0.03 can enhance the value of Hc up to ∼200% while maintaining the FM state at room temperature. As the doping level increases, TC decreases, whereas Hc increases up to 7 kOe at x = 0.12, which is the highest Hc reported so far. The FM characteristic is almost suppressed at x = 0.68 and a spin glass state appears. The enhancement of Hc resulting from Ni doping can be attributed to domain pinning induced by substitutional Ni atoms, as evidenced by the decrease in magnetic anisotropy energy in the crystals upon Ni doping. Our findings provide a highly effective way to control the Hc of the 2D vdW FM metal Fe3GaTe2 for the realization of Fe3GaTe2 based room-temperature operating spintronic devices.
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Affiliation(s)
- Hyo-Bin Ahn
- SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 16419, Korea
| | - Soon-Gil Jung
- Department of Physics Education, Sunchon National University, Suncheon 57922, Korea
| | - Hyungjong Lim
- School of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Korea.
| | - Kwangsu Kim
- Department of Physics, University of Ulsan, Ulsan 44619, Korea
- Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Sanghoon Kim
- Department of Physics, University of Ulsan, Ulsan 44619, Korea
| | - Tae-Eon Park
- Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Tuson Park
- Center for Quantum Materials and Superconductivity (CQMS), Sungkyunkwan University, Suwon 16419, Korea.
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Korea
| | - Changgu Lee
- SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 16419, Korea
- School of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Korea.
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Chen X, Wang H, Li M, Hao Q, Cai M, Dai H, Chen H, Xing Y, Liu J, Wang X, Zhai T, Zhou X, Han JB. Manipulation and Optical Detection of Artificial Topological Phenomena in 2D Van der Waals Fe 5 GeTe 2 /MnPS 3 Heterostructures. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023:e2207617. [PMID: 37327250 PMCID: PMC10401167 DOI: 10.1002/advs.202207617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 04/20/2023] [Indexed: 06/18/2023]
Abstract
2D ferromagnet is a good platform to investigate topological effects and spintronic devices owing to its rich spin structures and excellent external-field tunability. The appearance of the topological Hall Effect (THE) is often regarded as an important sign of the generation of chiral spin textures, like magnetic vortexes or skyrmions. Here, interface engineering and an in-plane current are used to modulate the magnetic properties of the nearly room-temperature 2D ferromagnet Fe5 GeTe2 . An artificial topology phenomenon is observed in the Fe5 GeTe2 /MnPS3 heterostructure by using both anomalous Hall Effect and reflective magnetic circular dichroism (RMCD) measurements. Through tuning the applied current and the RMCD laser wavelength, the amplitude of the humps and dips observed in the hysteresis loops can be modulated accordingly. Magnetic field-dependent hysteresis loops demonstrate that the observed artificial topological phenomena are induced by the generation and annihilation of the magnetic domains. This work provides an optical method for investigating the topological-like effects in magnetic structures and proposes an effective way to modulate the magnetic properties of magnetic materials, which is important for developing magnetic and spintronic devices in van der Waals magnetic materials.
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Affiliation(s)
- Xiaodie Chen
- Wuhan National High Magnetic Field Center and Department of Physics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Haoyun Wang
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Manshi Li
- Wuhan National High Magnetic Field Center and Department of Physics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Qinghua Hao
- Wuhan National High Magnetic Field Center and Department of Physics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Menghao Cai
- Wuhan National High Magnetic Field Center and Department of Physics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Hongwei Dai
- Wuhan National High Magnetic Field Center and Department of Physics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Hongjing Chen
- Wuhan National High Magnetic Field Center and Department of Physics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Yuntong Xing
- Wuhan National High Magnetic Field Center and Department of Physics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Jie Liu
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Xia Wang
- School of Elementary Education, Wuhan City Polytechnic College, Wuhan, 430074, P. R. China
| | - Tianyou Zhai
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Xing Zhou
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Jun-Bo Han
- Wuhan National High Magnetic Field Center and Department of Physics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
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Wang H, Lu H, Guo Z, Li A, Wu P, Li J, Xie W, Sun Z, Li P, Damas H, Friedel AM, Migot S, Ghanbaja J, Moreau L, Fagot-Revurat Y, Petit-Watelot S, Hauet T, Robertson J, Mangin S, Zhao W, Nie T. Interfacial engineering of ferromagnetism in wafer-scale van der Waals Fe 4GeTe 2 far above room temperature. Nat Commun 2023; 14:2483. [PMID: 37120587 PMCID: PMC10148834 DOI: 10.1038/s41467-023-37917-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 04/05/2023] [Indexed: 05/01/2023] Open
Abstract
Despite recent advances in exfoliated vdW ferromagnets, the widespread application of 2D magnetism requires a Curie temperature (Tc) above room temperature as well as a stable and controllable magnetic anisotropy. Here we demonstrate a large-scale iron-based vdW material Fe4GeTe2 with the Tc reaching ~530 K. We confirmed the high-temperature ferromagnetism by multiple characterizations. Theoretical calculations suggested that the interface-induced right shift of the localized states for unpaired Fe d electrons is the reason for the enhanced Tc, which was confirmed by ultraviolet photoelectron spectroscopy. Moreover, by precisely tailoring Fe concentration we achieved arbitrary control of magnetic anisotropy between out-of-plane and in-plane without inducing any phase disorders. Our finding sheds light on the high potential of Fe4GeTe2 in spintronics, which may open opportunities for room-temperature application of all-vdW spintronic devices.
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Affiliation(s)
- Hangtian Wang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China
- Universite de Lorraine, Institut Jean Lamour, UMR CNRS 7198, Nancy, France
| | - Haichang Lu
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China.
- Engineering Department, Cambridge University, Cambridge, CB2 1PZ, UK.
| | - Zongxia Guo
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China
- Universite de Lorraine, Institut Jean Lamour, UMR CNRS 7198, Nancy, France
| | - Ang Li
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China
| | - Peichen Wu
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China
| | - Jing Li
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China
| | - Weiran Xie
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China
| | - Zhimei Sun
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Peng Li
- Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA
| | - Héloïse Damas
- Universite de Lorraine, Institut Jean Lamour, UMR CNRS 7198, Nancy, France
| | - Anna Maria Friedel
- Universite de Lorraine, Institut Jean Lamour, UMR CNRS 7198, Nancy, France
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Sylvie Migot
- Universite de Lorraine, Institut Jean Lamour, UMR CNRS 7198, Nancy, France
| | - Jaafar Ghanbaja
- Universite de Lorraine, Institut Jean Lamour, UMR CNRS 7198, Nancy, France
| | - Luc Moreau
- Universite de Lorraine, Institut Jean Lamour, UMR CNRS 7198, Nancy, France
| | | | | | - Thomas Hauet
- Universite de Lorraine, Institut Jean Lamour, UMR CNRS 7198, Nancy, France
| | - John Robertson
- Engineering Department, Cambridge University, Cambridge, CB2 1PZ, UK
| | - Stéphane Mangin
- Universite de Lorraine, Institut Jean Lamour, UMR CNRS 7198, Nancy, France.
| | - Weisheng Zhao
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China.
| | - Tianxiao Nie
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China.
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35
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Li C, Li M, Li Y, He T, Liu Y, Zhang X, Dai X, Liu G. Two-dimensional half-metallicity and fully spin-polarized topological fermions in monolayer EuOBr. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:264002. [PMID: 36990099 DOI: 10.1088/1361-648x/acc8b2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 03/29/2023] [Indexed: 06/19/2023]
Abstract
Two-dimensional (2D) half-metal and topological states have been the current research focus in condensed matter physics. Herein, we report a novel 2D material named EuOBr monolayer, which can simultaneously show 2D half-metal and topological fermions. This material shows a metallic state in the spin-up channel but a large insulating gap of 4.38 eV in the spin-down channel. In the conducting spin channel, the EuOBr monolayer shows the coexistence of Weyl points and nodal-lines near the Fermi level. These nodal-lines are classified by type-I, hybrid, closed, and open nodal-lines. The symmetry analysis suggests these nodal-lines are protected by the mirror symmetry, which cannot be broken even spin-orbit coupling is included because the ground magnetization direction in the material is out-of-plane [001]. The topological fermions in the EuOBr monolayer are fully spin-polarized, which can be meaningful for future applications in topological spintronic nano-devices.
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Affiliation(s)
- Chenyao Li
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, People's Republic of China
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, People's Republic of China
| | - Minghang Li
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, People's Republic of China
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, People's Republic of China
| | - Yefeng Li
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, People's Republic of China
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, People's Republic of China
| | - Tingli He
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, People's Republic of China
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, People's Republic of China
| | - Ying Liu
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, People's Republic of China
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, People's Republic of China
| | - Xiaoming Zhang
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, People's Republic of China
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, People's Republic of China
| | - Xuefang Dai
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, People's Republic of China
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, People's Republic of China
| | - Guodong Liu
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, People's Republic of China
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, People's Republic of China
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36
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Zhao B, Ngaloy R, Ghosh S, Ershadrad S, Gupta R, Ali K, Hoque AM, Karpiak B, Khokhriakov D, Polley C, Thiagarajan B, Kalaboukhov A, Svedlindh P, Sanyal B, Dash SP. A Room-Temperature Spin-Valve with van der Waals Ferromagnet Fe 5 GeTe 2 /Graphene Heterostructure. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209113. [PMID: 36641649 DOI: 10.1002/adma.202209113] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/07/2022] [Indexed: 06/17/2023]
Abstract
The discovery of van der Waals (vdW) magnets opened a new paradigm for condensed matter physics and spintronic technologies. However, the operations of active spintronic devices with vdW ferromagnets are limited to cryogenic temperatures, inhibiting their broader practical applications. Here, the robust room-temperature operation of lateral spin-valve devices using the vdW itinerant ferromagnet Fe5 GeTe2 in heterostructures with graphene is demonstrated. The room-temperature spintronic properties of Fe5 GeTe2 are measured at the interface with graphene with a negative spin polarization. Lateral spin-valve and spin-precession measurements provide unique insights by probing the Fe5 GeTe2 /graphene interface spintronic properties via spin-dynamics measurements, revealing multidirectional spin polarization. Density functional theory calculations in conjunction with Monte Carlo simulations reveal significantly canted Fe magnetic moments in Fe5 GeTe2 along with the presence of negative spin polarization at the Fe5 GeTe2 /graphene interface. These findings open opportunities for vdW interface design and applications of vdW-magnet-based spintronic devices at ambient temperatures.
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Affiliation(s)
- Bing Zhao
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
| | - Roselle Ngaloy
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
| | - Sukanya Ghosh
- Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden
| | - Soheil Ershadrad
- Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden
| | - Rahul Gupta
- Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden
- Department of Materials Science and Engineering, Uppsala University, Box 35, Uppsala, SE-751 03, Sweden
| | - Khadiza Ali
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
- MAX IV Laboratory, Lund University, Lund, SE-221 00, Sweden
| | - Anamul Md Hoque
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
| | - Bogdan Karpiak
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
| | - Dmitrii Khokhriakov
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
| | - Craig Polley
- MAX IV Laboratory, Lund University, Lund, SE-221 00, Sweden
| | | | - Alexei Kalaboukhov
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
| | - Peter Svedlindh
- Department of Materials Science and Engineering, Uppsala University, Box 35, Uppsala, SE-751 03, Sweden
| | - Biplab Sanyal
- Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden
| | - Saroj P Dash
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
- Graphene Center, Chalmers University of Technology, Göteborg, SE-41296, Sweden
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37
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Basak K, Ghosh M, Chowdhury S, Jana D. Theoretical studies on electronic, magnetic and optical properties of two dimensional transition metal trihalides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:233001. [PMID: 36854185 DOI: 10.1088/1361-648x/acbffb] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 02/28/2023] [Indexed: 06/18/2023]
Abstract
Two dimensional transition metal trihalides have drawn attention over the years due to their intrinsic ferromagnetism and associated large anisotropy at nanoscale. The interactions involved in these layered structures are of van der Waals types which are important for exfoliation to different thin samples. This enables one to compare the journey of physical properties from bulk structures to monolayer counterpart. In this topical review, the modulation of electronic, magnetic and optical properties by strain engineering, alloying, doping, defect engineering etc have been discussed extensively. The results obtained by first principle density functional theory calculations are verified by recent experimental observations. The relevant experimental synthesis of different morphological transition metal trihalides are highlighted. The feasibility of such routes may indicate other possible heterostructures. Apart from spintronics based applications, transition metal trihalides are potential candidates in sensing and data storage. Moreover, high thermoelectric figure of merit of chromium trihalides at higher temperatures leads to the possibility of multi-purpose applications. We hope this review will give important directions to further research in transition metal trihalide systems having tunable band gap with reduced dimensionalities.
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Affiliation(s)
- Krishnanshu Basak
- Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Mainak Ghosh
- Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Suman Chowdhury
- S.N. Bose National Centre for Basic Sciences, JD-III Salt Lake City, Kolkata 700098, India
- Department of Physics, Shiv Nadar University, Greater Noida, Uttar Pradesh 201314, India
| | - Debnarayan Jana
- Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700009, India
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38
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Georgopoulou-Kotsaki E, Pappas P, Lintzeris A, Tsipas P, Fragkos S, Markou A, Felser C, Longo E, Fanciulli M, Mantovan R, Mahfouzi F, Kioussis N, Dimoulas A. Significant enhancement of ferromagnetism above room temperature in epitaxial 2D van der Waals ferromagnet Fe 5-δGeTe 2/Bi 2Te 3 heterostructures. NANOSCALE 2023; 15:2223-2233. [PMID: 36625389 DOI: 10.1039/d2nr04820e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Two-dimensional (2D) van der Waals (vdW) ferromagnetic metals FexGeTe2 with x = 3-5 have raised significant interest in the scientific community. Fe5GeTe2 shows prospects for spintronic applications since the Curie temperature Tc has been reported near or higher than 300 K. In the present work, epitaxial Fe5-δGeTe2 (FGT) heterostructures were grown by Molecular Beam Epitaxy (MBE) on insulating crystalline substrates. The FGT films were combined with Bi2Te3 topological insulator (TI) aiming to investigate the possible beneficial effect of the TI on the magnetic properties of FGT. FGT/Bi2Te3 films were compared to FGT capped only with AlOx to prevent oxidation. SQUID and MOKE measurements revealed that the growth of Bi2Te3 TI on FGT films significantly enhances the saturation magnetization of FGT as well as the Tc well above room temperature (RT) reaching record values of 570 K. First-principles calculations predict a shift of the Fermi level and an associated enhancement of the majority spin (primarily) as well as the total density of states at the Fermi level suggesting that effective doping of FGT from Bi2Te3 could explain the enhancement of ferromagnetism in FGT. It is also predicted that strain induced stabilization of a high magnetic moment phase in FGT/Bi2Te3 could be an alternative explanation of magnetization and Tc enhancement. Ferromagnetic resonance measurements evidence an enhanced broadening in the FGT/Bi2Te3 heterostructure when compared to FGT. We obtain a large spin mixing conductance of g↑↓eff = 4.4 × 1020 m-2, which demonstrates the great potential of FGT/Bi2Te3 systems for spin-charge conversion applications at room temperature.
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Affiliation(s)
- E Georgopoulou-Kotsaki
- National Centre for Scientific Research "Demokritos", Institute of Nanoscience and Nanotechnology, Agia Paraskevi, 15341, Athens, Greece.
- Section of Condensed Matter Physics, Department of Physics, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15784, Athens, Greece
| | - P Pappas
- National Centre for Scientific Research "Demokritos", Institute of Nanoscience and Nanotechnology, Agia Paraskevi, 15341, Athens, Greece.
| | - A Lintzeris
- National Centre for Scientific Research "Demokritos", Institute of Nanoscience and Nanotechnology, Agia Paraskevi, 15341, Athens, Greece.
- Department of Physics, National Technical University of Athens, School of Applied Mathematical and Physical Sciences, 15780, Athens, Greece
| | - P Tsipas
- National Centre for Scientific Research "Demokritos", Institute of Nanoscience and Nanotechnology, Agia Paraskevi, 15341, Athens, Greece.
| | - S Fragkos
- National Centre for Scientific Research "Demokritos", Institute of Nanoscience and Nanotechnology, Agia Paraskevi, 15341, Athens, Greece.
- Department of Mechanical Engineering, University of West Attica, 12241 Athens, Greece
| | - A Markou
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - C Felser
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - E Longo
- Institute for Microelectronics and Microsystems, CNR-IMM Unit of Agrate Brianza, Via C. Olivetti 2, 20864 Agrate Brianza, Italy
| | - M Fanciulli
- Department of Material Science, University of Milano Bicocca, Via R. Cozzi 55, Milan 20125, Italy
| | - R Mantovan
- Institute for Microelectronics and Microsystems, CNR-IMM Unit of Agrate Brianza, Via C. Olivetti 2, 20864 Agrate Brianza, Italy
| | - F Mahfouzi
- Department of Physics and Astronomy, California State University Northridge, Northridge, CA 91330-8268, USA
| | - N Kioussis
- Department of Physics and Astronomy, California State University Northridge, Northridge, CA 91330-8268, USA
| | - A Dimoulas
- National Centre for Scientific Research "Demokritos", Institute of Nanoscience and Nanotechnology, Agia Paraskevi, 15341, Athens, Greece.
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Zhang Z, Wang Y, Zhao Z, Song W, Zhou X, Li Z. Interlayer Chemical Modulation of Phase Transitions in Two-Dimensional Metal Chalcogenides. Molecules 2023; 28:molecules28030959. [PMID: 36770625 PMCID: PMC9921675 DOI: 10.3390/molecules28030959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/15/2023] [Accepted: 01/16/2023] [Indexed: 01/21/2023] Open
Abstract
Two-dimensional metal chalcogenides (2D-MCs) with complex interactions are usually rich in phase transition behavior, such as superconductivity, charge density wave (CDW), and magnetic transitions, which hold great promise for the exploration of exciting physical properties and functional applications. Interlayer chemical modulation, as a renewed surface modification method, presents congenital advantages to regulate the phase transitions of 2D-MCs due to its confined space, strong guest-host interactions, and local and reversible modulation without destructing the host lattice, whereby new phenomena and functionalities can be produced. Herein, recent achievements in the interlayer chemical modulation of 2D-MCs are reviewed from the aspects of superconducting transition, CDW transition, semiconductor-to-metal transition, magnetic phase transition, and lattice transition. We systematically discuss the roles of charge transfer, spin coupling, and lattice strain on the modulation of phase transitions in the guest-host architectures of 2D-MCs established by electrochemical intercalation, solution-processed intercalation, and solid-state intercalation. New physical phenomena, new insight into the mechanism of phase transitions, and derived functional applications are presented. Finally, a prospectus of the challenges and opportunities of interlayer chemical modulation for future research is pointed out.
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Affiliation(s)
- Zhi Zhang
- School of Physics, Frontiers Science Center for Mobile Information Communication and Security, Southeast University, Nanjing 211189, China
| | - Yi Wang
- School of Physics, Frontiers Science Center for Mobile Information Communication and Security, Southeast University, Nanjing 211189, China
| | - Zelin Zhao
- School of Physics, Frontiers Science Center for Mobile Information Communication and Security, Southeast University, Nanjing 211189, China
| | - Weijing Song
- School of Physics, Frontiers Science Center for Mobile Information Communication and Security, Southeast University, Nanjing 211189, China
| | - Xiaoli Zhou
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Zejun Li
- School of Physics, Frontiers Science Center for Mobile Information Communication and Security, Southeast University, Nanjing 211189, China
- Purple Mountain Laboratories, Nanjing 211111, China
- Correspondence:
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40
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Chen H, Asif S, Dolui K, Wang Y, Támara-Isaza J, Goli VMLDP, Whalen M, Wang X, Chen Z, Zhang H, Liu K, Jariwala D, Jungfleisch MB, Chakraborty C, May AF, McGuire MA, Nikolic BK, Xiao JQ, Ku MJH. Above-Room-Temperature Ferromagnetism in Thin van der Waals Flakes of Cobalt-Substituted Fe 5GeTe 2. ACS APPLIED MATERIALS & INTERFACES 2023; 15:3287-3296. [PMID: 36602594 DOI: 10.1021/acsami.2c18028] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Two-dimensional (2D) magnetic van der Waals materials provide a powerful platform for studying the fundamental physics of low-dimensional magnetism, engineering novel magnetic phases, and enabling thin and highly tunable spintronic devices. To realize high-quality and practical devices for such applications, there is a critical need for robust 2D magnets with ordering temperatures above room temperature that can be created via exfoliation. Here, the study of exfoliated flakes of cobalt-substituted Fe5GeTe2 (CFGT) exhibiting magnetism above room temperature is reported. Via quantum magnetic imaging with nitrogen-vacancy centers in diamond, ferromagnetism at room temperature was observed in CFGT flakes as thin as 16 nm corresponding to 16 layers. This result expands the portfolio of thin room-temperature 2D magnet flakes exfoliated from robust single crystals that reach a thickness regime relevant to practical spintronic applications. The Curie temperature Tc of CFGT ranges from 310 K in the thinnest flake studied to 328 K in the bulk. To investigate the prospect of high-temperature monolayer ferromagnetism, Monte Carlo calculations were performed, which predicted a high value of Tc of ∼270 K in CFGT monolayers. Pathways toward further enhancing monolayer Tc are discussed. These results support CFGT as a promising platform for realizing high-quality room-temperature 2D magnet devices.
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Affiliation(s)
- Hang Chen
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware19716, United States
| | - Shahidul Asif
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware19716, United States
| | - Kapildeb Dolui
- Lomare Technologies Ltd., 6 London Street, LondonEC3R 7LP, United Kingdom
| | - Yang Wang
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware19716, United States
| | - Jeyson Támara-Isaza
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware19716, United States
- Departamento de Física, Universidad Nacional de Colombia, Bogotá D.C.110851, Colombia
| | - V M L Durga Prasad Goli
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware19716, United States
| | - Matthew Whalen
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware19716, United States
| | - Xinhao Wang
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware19716, United States
| | - Zhijie Chen
- Department of Physics, Georgetown University, Washington, District of Columbia20057, United States
| | - Huiqin Zhang
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania19104, United States
| | - Kai Liu
- Department of Physics, Georgetown University, Washington, District of Columbia20057, United States
| | - Deep Jariwala
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania19104, United States
| | - M Benjamin Jungfleisch
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware19716, United States
| | - Chitraleema Chakraborty
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware19716, United States
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware19716, United States
| | - Andrew F May
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Michael A McGuire
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Branislav K Nikolic
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware19716, United States
| | - John Q Xiao
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware19716, United States
| | - Mark J H Ku
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware19716, United States
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware19716, United States
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41
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Zhang C, Liu C, Zhang J, Yuan Y, Wen Y, Li Y, Zheng D, Zhang Q, Hou Z, Yin G, Liu K, Peng Y, Zhang XX. Room-Temperature Magnetic Skyrmions and Large Topological Hall Effect in Chromium Telluride Engineered by Self-Intercalation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2205967. [PMID: 36245330 DOI: 10.1002/adma.202205967] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/06/2022] [Indexed: 06/16/2023]
Abstract
Room-temperature magnetic skyrmion materials exhibiting robust topological Hall effect (THE) are crucial for novel nano-spintronic devices. However, such skyrmion-hosting materials are rare in nature. In this study, a self-intercalated transition metal dichalcogenide Cr1+ x Te2 with a layered crystal structure that hosts room-temperature skyrmions and exhibits large THE is reported. By tuning the self-intercalate concentration, a monotonic control of Curie temperature from 169 to 333 K and a magnetic anisotropy transition from out-of-plane to the in-plane configuration are achieved. Based on the intercalation engineering, room-temperature skyrmions are successfully created in Cr1.53 Te2 with a Curie temperature of 295 K and a relatively weak perpendicular magnetic anisotropy. Remarkably, a skyrmion-induced topological Hall resistivity as large as ≈106 nΩ cm is observed at 290 K. Moreover, a sign reversal of THE is also found at low temperatures, which can be ascribed to other topological spin textures having an opposite topological charge to that of the skyrmions. Therefore, chromium telluride can be a new paradigm of the skyrmion material family with promising prospects for future device applications.
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Affiliation(s)
- Chenhui Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Chen Liu
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Junwei Zhang
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Youyou Yuan
- Core Labs, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Yan Wen
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Yan Li
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Dongxing Zheng
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Qiang Zhang
- Core Technology Platforms, New York University Abu Dhabi, Abu Dhabi, 129188, United Arab Emirates
| | - Zhipeng Hou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Gen Yin
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Kai Liu
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Yong Peng
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Xi-Xiang Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
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42
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Jiang H, Zang Z, Wang X, Que H, Wang L, Si K, Zhang P, Ye Y, Gong Y. Thickness-Tunable Growth of Composition-Controllable Two-Dimensional Fe xGeTe 2. NANO LETTERS 2022; 22:9477-9484. [PMID: 36383484 DOI: 10.1021/acs.nanolett.2c03562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Two-dimensional (2D) magnetic materials provide an ideal platform for investigating novel magnetism and spin behavior in low-dimensional systems while being restricted by the deficiency of accurate bottom-up synthesis. To overcome this difficulty, a facile and universal flux-assisted growth (FAG) method is proposed to synthesize the multicomponent FexGeTe2 (x = 3-5) with different Fe contents and even alloyed with hetero metal atoms. This one-to-one method ensures the stoichiometry consistency from the FexGeTe2 and MyFe5-yGeTe2 (M = Co, Ni) bulk crystal precursors to the 2D nanosheets, with controllable composition. Tuning the growth temperatures can provide thickness-tunable products. Changeable magnetic properties of FexGeTe2 and alloyed CoyFe5-yGeTe2 are substantiated by the superconducting quantum interference device and reflective magnetic circular dichroism. This method generates thickness-tunable high-crystallinity FexGeTe2 samples without phase separation and exhibits a high tolerance to different substrates and a large temperature window, providing a new avenue to synthesize and explore such multicomponent 2D magnets and even the alloyed ones.
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Affiliation(s)
- Huaning Jiang
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| | - Zhihao Zang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Xingguo Wang
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| | - Haifeng Que
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| | - Lei Wang
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| | - Kunpeng Si
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| | - Peng Zhang
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| | - Yu Ye
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Yongji Gong
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
- Key Laboratory of Intelligent Sensing Materials and Chip Integration Technology of Zhejiang Province, Hangzhou 310051, China
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43
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Min KH, Lee DH, Choi SJ, Lee IH, Seo J, Kim DW, Ko KT, Watanabe K, Taniguchi T, Ha DH, Kim C, Shim JH, Eom J, Kim JS, Jung S. Tunable spin injection and detection across a van der Waals interface. NATURE MATERIALS 2022; 21:1144-1149. [PMID: 35927432 DOI: 10.1038/s41563-022-01320-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
Van der Waals heterostructures with two-dimensional magnets offer a magnetic junction with an atomically sharp and clean interface. This attribute ensures that the magnetic layers maintain their intrinsic spin-polarized electronic states and spin-flipping scattering processes at a minimum level, a trait that can expand spintronic device functionalities. Here, using a van der Waals assembly of ferromagnetic Fe3GeTe2 with non-magnetic hexagonal boron nitride and WSe2 layers, we demonstrate electrically tunable, highly transparent spin injection and detection across the van der Waals interfaces. By varying an electrical bias, the net spin polarization of the injected carriers can be modulated and reversed in polarity, which leads to sign changes of the tunnelling magnetoresistance. We attribute the spin polarization reversals to sizable contributions from high-energy localized spin states in the metallic ferromagnet, so far inaccessible in conventional magnetic junctions. Such tunability of the spin-valve operations opens a promising route for the electronic control of next-generation low-dimensional spintronic device applications.
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Affiliation(s)
- Keun-Hong Min
- Interdisciplinary Materials Measurement Institute, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
- Department of Physics and Astronomy, Sejong University, Seoul, Republic of Korea
| | - Duk Hyun Lee
- Interdisciplinary Materials Measurement Institute, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Sang-Jun Choi
- Institute for Theoretical Physics and Astrophysics, University of Würzburg, Würzburg, Germany
| | - In-Ho Lee
- Interdisciplinary Materials Measurement Institute, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Junho Seo
- Department of Physics, Pohang University of Science and Technology, Pohang, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang, Republic of Korea
| | - Dong Wook Kim
- Department of Chemistry, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Kyung-Tae Ko
- Research Center for Materials Analysis, Korea Basic Science Institute, Daejeon, Republic of Korea
| | - Kenji Watanabe
- Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan
| | - Dong Han Ha
- Interdisciplinary Materials Measurement Institute, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Changyoung Kim
- Department of Physics and Astronomy, Seoul National University, Seoul, Republic of Korea
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, Republic of Korea
| | - Ji Hoon Shim
- Department of Physics, Pohang University of Science and Technology, Pohang, Republic of Korea
- Department of Chemistry, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Jonghwa Eom
- Department of Physics and Astronomy, Sejong University, Seoul, Republic of Korea.
| | - Jun Sung Kim
- Department of Physics, Pohang University of Science and Technology, Pohang, Republic of Korea.
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang, Republic of Korea.
| | - Suyong Jung
- Interdisciplinary Materials Measurement Institute, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea.
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44
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Zhang C, Liu C, Zhang S, Zhou B, Guan C, Ma Y, Algaidi H, Zheng D, Li Y, He X, Zhang J, Li P, Hou Z, Yin G, Liu K, Peng Y, Zhang XX. Magnetic Skyrmions with Unconventional Helicity Polarization in a Van Der Waals Ferromagnet. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2204163. [PMID: 35975291 DOI: 10.1002/adma.202204163] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 08/10/2022] [Indexed: 06/15/2023]
Abstract
Skyrmion helicity, which defines the spin swirling direction, is a fundamental parameter that may be utilized to encode data bits in future memory devices. Generally, in centrosymmetric ferromagnets, dipole skyrmions with helicity of -π/2 and π/2 are degenerate in energy, leading to equal populations of both helicities. On the other hand, in chiral materials where the Dzyaloshinskii-Moriya interaction (DMI) prevails and the dipolar interaction is negligible, only a preferred helicity is selected by the type of DMI. However, whether there is a rigid boundary between these two regimes remains an open question. Herein, the observation of dipole skyrmions with unconventional helicity polarization in a van der Waals ferromagnet, Fe5- δ GeTe2 , is reported. Combining magnetometry, Lorentz transmission electron microscopy, electrical transport measurements, and micromagnetic simulations, the short-range superstructures in Fe5- δ GeTe2 resulting in a localized DMI contribution, which breaks the degeneracy of the opposite helicities and leads to the helicity polarization, is demonstrated. Therefore, the helicity feature in Fe5- δ GeTe2 is controlled by both the dipolar interaction and DMI that the former leads to Bloch-type skyrmions with helicity of ±π/2 whereas the latter breaks the helicity degeneracy. This work provides new insights into the skyrmion topology in van der Waals materials.
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Affiliation(s)
- Chenhui Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Chen Liu
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Senfu Zhang
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Bojian Zhou
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Chaoshuai Guan
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Yinchang Ma
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Hanin Algaidi
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Dongxing Zheng
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Yan Li
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Xin He
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Junwei Zhang
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Peng Li
- State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Zhipeng Hou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China
- National Center for International Research on Green Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Gen Yin
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Kai Liu
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Yong Peng
- School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Xi-Xiang Zhang
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
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45
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Guo Y, Zhao Y, Zhou S, Zhao J. Oxidation behavior of layered Fe nGeTe 2 ( n = 3, 4, 5) and Cr 2Ge 2Te 6 governed by interlayer coupling. NANOSCALE 2022; 14:11452-11460. [PMID: 35904500 DOI: 10.1039/d2nr02375j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Layered magnetic materials have recently received tremendous attention due to an attractive combination of functional properties suitable for nanoelectronics and spintronic applications. Enhancing the air stability of the material is a prerequisite for long-term durability of devices. However, the oxidation mechanism of layered magnetic materials is yet to be revealed. Herein we explore the oxidation behavior of monolayer and multilayer FenGeTe2 (n = 3, 4, 5) and Cr2Ge2Te6 using first-principles calculations. The results show that these monolayer systems are prone to be oxidized in ambient air. With increasing thickness, however, multilayer FenGeTe2 exhibits distinct oxidation behavior from its monolayer counterparts, originating from its unexpected strong interlayer coupling characterized by wavefunction overlapping of adjacent Te atoms between FenGeTe2 layers. Moreover, O2 adsorption does not severely deteriorate the magnetism of layered FenGeTe2 and Cr2Ge2Te6. Given the fact that oxidation properties can be altered by interlayer coupling, our work opens a paradigm for obtaining oxidation-resistant layered materials.
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Affiliation(s)
- Yu Guo
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
| | - Yanyan Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
| | - Si Zhou
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
| | - Jijun Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
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46
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Fujita R, Bassirian P, Li Z, Guo Y, Mawass MA, Kronast F, van der Laan G, Hesjedal T. Layer-Dependent Magnetic Domains in Atomically Thin Fe 5GeTe 2. ACS NANO 2022; 16:10545-10553. [PMID: 35802911 PMCID: PMC9331157 DOI: 10.1021/acsnano.2c01948] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Magnetic domain formation in two-dimensional (2D) materials gives perspectives into the fundamental origins of 2D magnetism and also motivates the development of advanced spintronics devices. However, the characterization of magnetic domains in atomically thin van der Waals (vdW) flakes remains challenging. Here, we employ X-ray photoemission electron microscopy (XPEEM) to perform layer-resolved imaging of the domain structures in the itinerant vdW ferromagnet Fe5GeTe2 which shows near room temperature bulk ferromagnetism and a weak perpendicular magnetic anisotropy (PMA). In the bulk limit, we observe the well-known labyrinth-type domains. Thinner flakes, on the other hand, are characterized by increasingly fragmented domains. While PMA is a characteristic property of Fe5GeTe2, we observe a spin-reorientation transition with the spins canting in-plane for flakes thinner than six layers. Notably, a bubble phase emerges in four-layer flakes. This thickness dependence, which clearly deviates from the single-domain behavior observed in other 2D magnetic materials, demonstrates the exciting prospect of stabilizing complex spin textures in 2D vdW magnets at relatively high temperatures.
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Affiliation(s)
- Ryuji Fujita
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Parks Road, Oxford, OX1
3PU, United Kingdom
| | - Pedram Bassirian
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Parks Road, Oxford, OX1
3PU, United Kingdom
- Max
Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Zhengxian Li
- School
of Physical Science and Technology, ShanghaiTech
University, Shanghai 201210, China
| | - Yanfeng Guo
- School
of Physical Science and Technology, ShanghaiTech
University, Shanghai 201210, China
| | - Mohamad A. Mawass
- Helmholtz-Zentrum
Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Florian Kronast
- Helmholtz-Zentrum
Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Gerrit van der Laan
- Diamond
Light Source, Harwell Science and Innovation
Campus, Didcot, OX11 0DE, United Kingdom
| | - Thorsten Hesjedal
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Parks Road, Oxford, OX1
3PU, United Kingdom
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47
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Li Z, Tang M, Huang J, Qin F, Ao L, Shen Z, Zhang C, Chen P, Bi X, Qiu C, Yu Z, Zhai K, Ideue T, Wang L, Liu Z, Tian Y, Iwasa Y, Yuan H. Magnetic Anisotropy Control with Curie Temperature above 400 K in a van der Waals Ferromagnet for Spintronic Device. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2201209. [PMID: 35448916 DOI: 10.1002/adma.202201209] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 04/07/2022] [Indexed: 06/14/2023]
Abstract
The technological appeal of van der Waals ferromagnetic materials is the ability to control magnetism under external fields with desired thickness toward novel spintronic applications. For practically useful devices, ferromagnetism above room temperature or tunable magnetic anisotropy is highly demanded but remains challenging. To date, only a few layered materials exhibit unambiguous ferromagnetic ordering at room temperature via gating techniques or interface engineering. Here, it is demonstrated that the magnetic anisotropy control and dramatic modulation of Curie temperature (Tc ) up to 400 K are realized in layered Fe5 GeTe2 via the high-pressure diamond-anvil-cell technique. Magnetic phases manifesting with in-plane anisotropic, out-of-plane anisotropic and nearly isotropic magnetic states can be tuned in a controllable way, depicted by the phase diagram with a maximum Tc up to 360 K. Remarkably, the Tc can be gradually enhanced to above 400 K owing to the Fermi surface evolution during a pressure loading-deloading process. Such an observation sheds light on the understanding and control of emergent magnetic states in practical spintronic applications.
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Affiliation(s)
- Zeya Li
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Ming Tang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
- School of Physics, Nanjing University, Nanjing, 210000, China
| | - Junwei Huang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Feng Qin
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Lingyi Ao
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Zhiwei Shen
- Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066000, China
| | - Caorong Zhang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
- School of Physics, Nanjing University, Nanjing, 210000, China
| | - Peng Chen
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Xiangyu Bi
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Caiyu Qiu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
| | - Zhipeng Yu
- Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066000, China
| | - Kun Zhai
- Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066000, China
| | - Toshiya Ideue
- Quantum Phase Electronic Center and Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8581, Japan
| | - Lin Wang
- Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066000, China
| | - Zhongyuan Liu
- Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066000, China
| | - Yongjun Tian
- Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066000, China
| | - Yoshihiro Iwasa
- Quantum Phase Electronic Center and Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan
- RIKEN Center for Emergent Matter Science, Hirosawa 2-1, Wako, 351-0198, Japan
| | - Hongtao Yuan
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210000, China
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48
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Verchenko VY, Stepanova AV, Bogach AV, Mironov AV, Shevelkov AV. Fe-Rich Ferromagnetic Cleavable Van der Waals Telluride Fe 5AsTe 2. Inorg Chem 2022; 61:9224-9230. [PMID: 35658443 DOI: 10.1021/acs.inorgchem.2c00800] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transition metal-based layered compounds with van der Waals gaps between the structural layers are a rich source of magnetic materials for spintronic applications. Bulk crystals can be cleaved, providing high-quality two-dimensional nanomaterials, which are promising for the manipulation of spins in spintronic devices and low power quantum logic interfaces. The layered van der Waals telluride Fe5AsTe2 can be synthesized by the high-temperature reaction of elements. In the crystal structure, Fe-rich structural layers with the composition of Fe4.58(4)AsTe2 are separated by the van der Waals gaps with no atoms in the interstitial region. Crystal growth employing chemical vapor transport reactions yields bulk cleavable crystals, which exhibit weak inherent ferromagnetism below the Curie temperature of TC = 48 K. In the ordered state, the magnetization shows a dual-slope behavior in low magnetic fields, indicating the compensated or canted nature of magnetism. Magnetic susceptibility and magnetization measurements reveal perpendicular magnetic anisotropy. The large Rhodes-Wohlfarth ratio of 4.6 indicates the itinerant nature of ferromagnetism in Fe5AsTe2.
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Affiliation(s)
- Valeriy Yu Verchenko
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.,National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | - Anna V Stepanova
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Alexey V Bogach
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Andrei V Mironov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Andrei V Shevelkov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
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49
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Chen X, Shao YT, Chen R, Susarla S, Hogan T, He Y, Zhang H, Wang S, Yao J, Ercius P, Muller DA, Ramesh R, Birgeneau RJ. Pervasive beyond Room-Temperature Ferromagnetism in a Doped van der Waals Magnet. PHYSICAL REVIEW LETTERS 2022; 128:217203. [PMID: 35687434 DOI: 10.1103/physrevlett.128.217203] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 04/28/2022] [Indexed: 06/15/2023]
Abstract
The existence of long-range magnetic order in low-dimensional magnetic systems, such as the quasi-two-dimensional van der Waals (vdW) magnets, has attracted intensive studies of new physical phenomena. The vdW Fe_{N}GeTe_{2} (N=3, 4, 5; FGT) family is exceptional, owing to its vast tunability of magnetic properties. In particular, a ferromagnetic ordering temperature (T_{C}) above room temperature at N=5 (F5GT) is observed. Here, our study shows that, by nickel (Ni) substitution of iron in F5GT, a record high T_{C}=478(6) K is achieved. Importantly, pervasive, beyond room-temperature ferromagnetism exists in almost the entire doping range of the phase diagram of Ni-F5GT. We argue that this striking observation in Ni-F5GT can be possibly due to several contributing factors, including increased 3D magnetic couplings due to the structural alterations.
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Affiliation(s)
- Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Physics Department, University of California, Berkeley, California 94720, USA
| | - Yu-Tsun Shao
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Rui Chen
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Sandhya Susarla
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Tom Hogan
- Quantum Design, Inc., San Diego, California 92121, USA
| | - Yu He
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Physics Department, University of California, Berkeley, California 94720, USA
- Department of Applied Physics, Yale University, New Haven, Connecticut, 06511, USA
| | - Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Siqi Wang
- NSF Nanoscale Science and Engineering Center (NSEC), 3112 Etcheverry Hall, University of California, Berkeley, California 94720, USA
| | - Jie Yao
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Peter Ercius
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, USA
| | - Ramamoorthy Ramesh
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Physics Department, University of California, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Robert J Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
- Physics Department, University of California, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
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50
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Wang QH, Bedoya-Pinto A, Blei M, Dismukes AH, Hamo A, Jenkins S, Koperski M, Liu Y, Sun QC, Telford EJ, Kim HH, Augustin M, Vool U, Yin JX, Li LH, Falin A, Dean CR, Casanova F, Evans RFL, Chshiev M, Mishchenko A, Petrovic C, He R, Zhao L, Tsen AW, Gerardot BD, Brotons-Gisbert M, Guguchia Z, Roy X, Tongay S, Wang Z, Hasan MZ, Wrachtrup J, Yacoby A, Fert A, Parkin S, Novoselov KS, Dai P, Balicas L, Santos EJG. The Magnetic Genome of Two-Dimensional van der Waals Materials. ACS NANO 2022; 16:6960-7079. [PMID: 35442017 PMCID: PMC9134533 DOI: 10.1021/acsnano.1c09150] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 02/23/2022] [Indexed: 05/23/2023]
Abstract
Magnetism in two-dimensional (2D) van der Waals (vdW) materials has recently emerged as one of the most promising areas in condensed matter research, with many exciting emerging properties and significant potential for applications ranging from topological magnonics to low-power spintronics, quantum computing, and optical communications. In the brief time after their discovery, 2D magnets have blossomed into a rich area for investigation, where fundamental concepts in magnetism are challenged by the behavior of spins that can develop at the single layer limit. However, much effort is still needed in multiple fronts before 2D magnets can be routinely used for practical implementations. In this comprehensive review, prominent authors with expertise in complementary fields of 2D magnetism (i.e., synthesis, device engineering, magneto-optics, imaging, transport, mechanics, spin excitations, and theory and simulations) have joined together to provide a genome of current knowledge and a guideline for future developments in 2D magnetic materials research.
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Affiliation(s)
- Qing Hua Wang
- Materials
Science and Engineering, School for Engineering of Matter, Transport
and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Amilcar Bedoya-Pinto
- NISE
Department, Max Planck Institute of Microstructure
Physics, 06120 Halle, Germany
- Instituto
de Ciencia Molecular (ICMol), Universitat
de València, 46980 Paterna, Spain
| | - Mark Blei
- Materials
Science and Engineering, School for Engineering of Matter, Transport
and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Avalon H. Dismukes
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Assaf Hamo
- Department
of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Sarah Jenkins
- Twist
Group,
Faculty of Physics, University of Duisburg-Essen, Campus Duisburg, 47057 Duisburg, Germany
| | - Maciej Koperski
- Institute
for Functional Intelligent Materials, National
University of Singapore, 117544 Singapore
| | - Yu Liu
- Condensed
Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Qi-Chao Sun
- Physikalisches
Institut, University of Stuttgart, 70569 Stuttgart, Germany
| | - Evan J. Telford
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
- Department
of Physics, Columbia University, New York, New York 10027, United States
| | - Hyun Ho Kim
- School
of Materials Science and Engineering, Department of Energy Engineering
Convergence, Kumoh National Institute of
Technology, Gumi 39177, Korea
| | - Mathias Augustin
- Institute
for Condensed Matter Physics and Complex Systems, School of Physics
and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, United Kingdom
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Uri Vool
- Department
of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
- John Harvard
Distinguished Science Fellows Program, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Jia-Xin Yin
- Laboratory
for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, New Jersey 08544, United States
| | - Lu Hua Li
- Institute
for Frontier Materials, Deakin University, Geelong Waurn Ponds Campus, Waurn Ponds, Victoria 3216, Australia
| | - Alexey Falin
- Institute
for Frontier Materials, Deakin University, Geelong Waurn Ponds Campus, Waurn Ponds, Victoria 3216, Australia
| | - Cory R. Dean
- Department
of Physics, Columbia University, New York, New York 10027, United States
| | - Fèlix Casanova
- CIC nanoGUNE
BRTA, 20018 Donostia - San Sebastián, Basque
Country, Spain
- IKERBASQUE,
Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
| | - Richard F. L. Evans
- Department
of Physics, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Mairbek Chshiev
- Université
Grenoble Alpes, CEA, CNRS, Spintec, 38000 Grenoble, France
- Institut
Universitaire de France, 75231 Paris, France
| | - Artem Mishchenko
- Department
of Physics and Astronomy, University of
Manchester, Manchester, M13 9PL, United Kingdom
- National
Graphene Institute, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Cedomir Petrovic
- Condensed
Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Rui He
- Department
of Electrical and Computer Engineering, Texas Tech University, 910 Boston Avenue, Lubbock, Texas 79409, United
States
| | - Liuyan Zhao
- Department
of Physics, University of Michigan, 450 Church Street, Ann Arbor, Michigan 48109, United States
| | - Adam W. Tsen
- Institute
for Quantum Computing and Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Brian D. Gerardot
- SUPA, Institute
of Photonics and Quantum Sciences, Heriot-Watt
University, Edinburgh EH14 4AS, United Kingdom
| | - Mauro Brotons-Gisbert
- SUPA, Institute
of Photonics and Quantum Sciences, Heriot-Watt
University, Edinburgh EH14 4AS, United Kingdom
| | - Zurab Guguchia
- Laboratory
for Muon Spin Spectroscopy, Paul Scherrer
Institute, CH-5232 Villigen PSI, Switzerland
| | - Xavier Roy
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Sefaattin Tongay
- Materials
Science and Engineering, School for Engineering of Matter, Transport
and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Ziwei Wang
- Department
of Physics and Astronomy, University of
Manchester, Manchester, M13 9PL, United Kingdom
- National
Graphene Institute, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - M. Zahid Hasan
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Princeton
Institute for Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, United States
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
| | - Joerg Wrachtrup
- Physikalisches
Institut, University of Stuttgart, 70569 Stuttgart, Germany
- Max Planck
Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Amir Yacoby
- Department
of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
- John A.
Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Albert Fert
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
- Department
of Materials Physics UPV/EHU, 20018 Donostia - San Sebastián, Basque Country, Spain
| | - Stuart Parkin
- NISE
Department, Max Planck Institute of Microstructure
Physics, 06120 Halle, Germany
| | - Kostya S. Novoselov
- Institute
for Functional Intelligent Materials, National
University of Singapore, 117544 Singapore
| | - Pengcheng Dai
- Department
of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Luis Balicas
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
- Department
of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Elton J. G. Santos
- Institute
for Condensed Matter Physics and Complex Systems, School of Physics
and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, United Kingdom
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
- Higgs Centre
for Theoretical Physics, The University
of Edinburgh, Edinburgh EH9 3FD, United Kingdom
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