1
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Shi B, Geng Y, Wang H, Yang J, Shang C, Wang M, Mi S, Huang J, Pan F, Gui X, Wang J, Liu J, Xu D, Zhang H, Qin J, Wang H, Hao L, Tian M, Cheng Z, Zheng G, Cheng P. FePd 2Te 2: An Anisotropic Two-Dimensional Ferromagnet with One-Dimensional Fe Chains. J Am Chem Soc 2024; 146:21546-21554. [PMID: 39048922 DOI: 10.1021/jacs.4c04910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Two-dimensional (2D) magnets have attracted significant attention in recent years due to their importance in the research on both fundamental physics and spintronic applications. Here, we report the discovery of a new ternary compound FePd2Te2. It features a layered quasi-2D crystal structure with 1D Fe zigzag chains extending along the b-axis in the cleavage plane. Single crystals of FePd2Te2 with centimeter size could be grown. Density functional theory calculations, mechanical exfoliation, and atomic force microscopy on these crystals reveal that they are 2D materials that can be thinned down to ∼5 nm. Magnetic characterization shows that FePd2Te2 is an easy-plane ferromagnet with TC ∼ 183 K and strong in-plane uniaxial magnetic anisotropy. Magnetoresistance and the anomalous Hall effect demonstrate that ferromagnetism could be maintained in FePd2Te2 flakes with large coercivity. A crystal twinning effect is observed by scanning tunneling microscopy which makes the Fe chains right angle bent in the cleavage plane and creates an intriguing spin texture. Besides, a large electronic specific heat coefficient of up to γ ∼ 32.4 mJ mol-1 K-2 suggests FePd2Te2 is a strongly correlated metal. Our results show that FePd2Te2 is a correlated anisotropic 2D magnet that may attract multidisciplinary research interests.
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Affiliation(s)
- Bingxian Shi
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
- Laboratory for Neutron Scattering, Department of Physics, Renmin University of China, Beijing 100872, China
| | - Yanyan Geng
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
| | - Hengning Wang
- Department of Physics, University of Science and Technology of China, Hefei 230031, Anhui, China
- Anhui Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Jianhui Yang
- Quzhou University, Quzhou, Zhejiang 32400, China
| | - Chenglin Shang
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
- Laboratory for Neutron Scattering, Department of Physics, Renmin University of China, Beijing 100872, China
| | - Manyu Wang
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
| | - Shuo Mi
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
| | - Jiale Huang
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
- Laboratory for Neutron Scattering, Department of Physics, Renmin University of China, Beijing 100872, China
| | - Feihao Pan
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
- Laboratory for Neutron Scattering, Department of Physics, Renmin University of China, Beijing 100872, China
| | - Xuejuan Gui
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
- Laboratory for Neutron Scattering, Department of Physics, Renmin University of China, Beijing 100872, China
| | - Jinchen Wang
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
- Laboratory for Neutron Scattering, Department of Physics, Renmin University of China, Beijing 100872, China
| | - Juanjuan Liu
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
- Laboratory for Neutron Scattering, Department of Physics, Renmin University of China, Beijing 100872, China
| | - Daye Xu
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
- Laboratory for Neutron Scattering, Department of Physics, Renmin University of China, Beijing 100872, China
| | - Hongxia Zhang
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
- Laboratory for Neutron Scattering, Department of Physics, Renmin University of China, Beijing 100872, China
| | - Jianfei Qin
- China Institute of Atomic Energy, PO Box 275-30, Beijing 102413, China
| | - Hongliang Wang
- China Institute of Atomic Energy, PO Box 275-30, Beijing 102413, China
| | - Lijie Hao
- China Institute of Atomic Energy, PO Box 275-30, Beijing 102413, China
| | - Mingliang Tian
- Anhui Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Zhihai Cheng
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
| | - Guolin Zheng
- Anhui Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Peng Cheng
- Department of Physics, Key Laboratory of Quantum State Construction and Manipulation, Ministry of Education, Renmin University of China, Beijing 100872, China
- Laboratory for Neutron Scattering, Department of Physics, Renmin University of China, Beijing 100872, China
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2
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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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3
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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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4
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Lim H, Ahn HB, Lee C. Magnetic properties of ferromagnetic nanoparticles of Fe xGeTe 2( x= 3, 5) directly exfoliated and dispersed in pure water. NANOTECHNOLOGY 2024; 35:395604. [PMID: 38959866 DOI: 10.1088/1361-6528/ad5e8a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 07/03/2024] [Indexed: 07/05/2024]
Abstract
FexGeTe2(x= 3, 5) are two-dimensional ferromagnetic (FM) materials that have gained significant attention from researchers due to their relatively high Curie temperature and tunability. However, the methods for preparing FM nanoparticles (FNPs) and large-area FexGeTe2films are still in the early stages. Here, we studied the magnetic properties of FexGeTe2FNPs exfoliated via wet exfoliation in pure water. The coercive field of Fe3GeTe2FNPs increases significantly, up to 60 times, while that of Fe5GeTe2only slightly increases from that of bulk crystals. Further investigation related to the dimension of nanoparticles and the Henkel plot analysis reveals that the variation in their coercive field stems from the material's thickness-dependent coercive field and the type of term that governs the interaction between single-domain nanoparticles. Our work demonstrates a facile method for preparing FNPs using van der Waals FM materials and tuning their magnetic properties.
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Affiliation(s)
- Hyunjong Lim
- School of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyo-Bin Ahn
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Changgu Lee
- School of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea
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5
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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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6
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Chen H, Tian W, Zhang L, Song P, Jia L, Chen J, Zhu Z, Feng YP, Loh KP. Highly Efficient Spin Injection and Readout Across Van Der Waals Interface. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2403073. [PMID: 38966892 DOI: 10.1002/smll.202403073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 06/25/2024] [Indexed: 07/06/2024]
Abstract
Spin injection, transport, and detection across the interface between a ferromagnet and a spin-carrying channel are crucial for energy-efficient spin logic devices. However, interfacial conductance mismatch, spin dephasing, and inefficient spin-to-charge conversion significantly reduce the efficiency of these processes. In this study, it is demonstrated that an all van der Waals heterostructure consisting of a ferromagnet (Fe3GeTe2) and Weyl semimetal enables a large spin readout efficiency. Specifically, a nonlocal spin readout signal of 150 mΩ and a local spin readout signal of 7.8 Ω is achieved, which reach the signal level useful for practical spintronic devices. The remarkable spin readout signal is attributed to suppressed spin dephasing channels at the vdW interfaces, long spin diffusion, and efficient charge-spin interconversion in Td-MoTe2. These findings highlight the potential of vdW heterostructures for spin Hall effect-enabled spin detection with high efficiency, opening up new possibilities for spin-orbit logic devices using vdW interfaces.
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Affiliation(s)
- Hao Chen
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Wanghao Tian
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Lishu Zhang
- Department of Physics, National University of Singapore, Singapore, 117551, Singapore
| | - Peng Song
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- CINTRA CNRS/NTU/THALES, UMI 3288, Research Techno Plaza, Singapore, 637553, Singapore
| | - Lanxin Jia
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Jingsheng Chen
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Zhifeng Zhu
- School of Information Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Yuan Ping Feng
- Department of Physics, National University of Singapore, Singapore, 117551, Singapore
| | - Kian Ping Loh
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
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7
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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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8
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Hu G, Guo H, Lv S, Li L, Wang Y, Han Y, Pan L, Xie Y, Yu W, Zhu K, Qi Q, Xian G, Zhu S, Shi J, Bao L, Lin X, Zhou W, Yang H, Gao HJ. Room‐Temperature Antisymmetric Magnetoresistance in van der Waals Ferromagnet Fe 3GaTe 2 Nanosheets. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2403154. [PMID: 38631700 DOI: 10.1002/adma.202403154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/08/2024] [Indexed: 04/19/2024]
Abstract
Van der Waals (vdW) ferromagnetic materials have emerged as a promising platform for the development of 2D spintronic devices. However, studies to date are restricted to vdW ferromagnetic materials with low Curie temperature (Tc) and small magnetic anisotropy. Here, a chemical vapor transport method is developed to synthesize a high-quality room-temperature ferromagnet, Fe3GaTe2 (c-Fe3GaTe2), which boasts a high Tc = 356 K and large perpendicular magnetic anisotropy. Due to the planar symmetry breaking, an unconventional room-temperature antisymmetric magnetoresistance (MR) is first observed in c-Fe3GaTe2 devices with step features, manifesting as three distinctive states of high, intermediate, and low resistance with the sweeping magnetic field. Moreover, the modulation of the antisymmetric MR is demonstrated by controlling the height of the surface steps. This work provides new routes to achieve magnetic random storage and logic devices by utilizing the room-temperature thickness-controlled antisymmetric MR and further design room-temperature 2D spintronic devices based on the vdW ferromagnet c-Fe3GaTe2.
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Affiliation(s)
- Guojing Hu
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Hui Guo
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Senhao Lv
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Linxuan Li
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yunhao Wang
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yechao Han
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lulu Pan
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Yulan Xie
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Weiqi Yu
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Ke Zhu
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qi Qi
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guoyu Xian
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shiyu Zhu
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jinan Shi
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lihong Bao
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Xiao Lin
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wu Zhou
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Haitao Yang
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Hong-Jun Gao
- Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
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9
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Chen L, Xie F, Sur S, Hu H, Paschen S, Cano J, Si Q. Emergent flat band and topological Kondo semimetal driven by orbital-selective correlations. Nat Commun 2024; 15:5242. [PMID: 38898039 PMCID: PMC11186837 DOI: 10.1038/s41467-024-49306-w] [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: 02/24/2023] [Accepted: 05/30/2024] [Indexed: 06/21/2024] Open
Abstract
Flat electronic bands are expected to show proportionally enhanced electron correlations, which may generate a plethora of novel quantum phases and unusual low-energy excitations. They are increasingly being pursued in d-electron-based systems with crystalline lattices that feature destructive electronic interference, where they are often topological. Such flat bands, though, are generically located far away from the Fermi energy, which limits their capacity to partake in the low-energy physics. Here we show that electron correlations produce emergent flat bands that are pinned to the Fermi energy. We demonstrate this effect within a Hubbard model, in the regime described by Wannier orbitals where an effective Kondo description arises through orbital-selective Mott correlations. Moreover, the correlation effect cooperates with symmetry constraints to produce a topological Kondo semimetal. Our results motivate a novel design principle for Weyl Kondo semimetals in a new setting, viz. d-electron-based materials on suitable crystal lattices, and uncover interconnections among seemingly disparate systems that may inspire fresh understandings and realizations of correlated topological effects in quantum materials and beyond.
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Affiliation(s)
- Lei Chen
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA
| | - Fang Xie
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA
| | - Shouvik Sur
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA
| | - Haoyu Hu
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA
- Donostia International Physics Center, P. Manuel de Lardizabal 4, 20018, Donostia-San Sebastian, Spain
| | - Silke Paschen
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040, Vienna, Austria
| | - Jennifer Cano
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
- Center for Computational Quantum Physics, Flatiron Institute, New York, NY, 10010, USA
| | - Qimiao Si
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA.
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10
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Choi GS, Park S, An ES, Bae J, Shin I, Kang BT, Won CJ, Cheong SW, Lee HW, Lee GH, Cho WJ, Kim JS. Highly Efficient Room-Temperature Spin-Orbit-Torque Switching in a Van der Waals Heterostructure of Topological Insulator and Ferromagnet. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2400893. [PMID: 38520060 DOI: 10.1002/advs.202400893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Indexed: 03/25/2024]
Abstract
All-Van der Waals (vdW)-material-based heterostructures with atomically sharp interfaces offer a versatile platform for high-performing spintronic functionalities at room temperature. One of the key components is vdW topological insulators (TIs), which can produce a strong spin-orbit-torque (SOT) through the spin-momentum locking of their topological surface state (TSS). However, the relatively low conductance of the TSS introduces a current leakage problem through the bulk states of the TI or the adjacent ferromagnetic metal layers, reducing the interfacial charge-to-spin conversion efficiency (qICS). Here, a vdW heterostructure is used consisting of atomically-thin layers of a bulk-insulating TI Sn-doped Bi1.1Sb0.9Te2S1 and a room-temperature ferromagnet Fe3GaTe2, to enhance the relative current ratio on the TSS up to ≈20%. The resulting qICS reaches ≈1.65 nm-1 and the critical current density Jc ≈0.9 × 106 Acm-2 at 300 K, surpassing the performance of TI-based and heavy-metal-based SOT devices. These findings demonstrate that an all-vdW heterostructure with thickness optimization offers a promising platform for efficient current-controlled magnetization switching at room temperature.
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Affiliation(s)
- Gyu Seung Choi
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Sungyu Park
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Eun-Su An
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Juhong Bae
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Inseob Shin
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Beom Tak Kang
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Choong Jae Won
- Center for Complex Phase of Materials, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Republic of Korea
- Laboratory for Pohang Emergent Materials, Department of Physics, POSTECH, Pohang, 37673, Republic of Korea
| | - Sang-Wook Cheong
- Center for Complex Phase of Materials, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Republic of Korea
- Laboratory for Pohang Emergent Materials, Department of Physics, POSTECH, Pohang, 37673, Republic of Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Hyun-Woo Lee
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Gil-Ho Lee
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Won Joon Cho
- Device Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Jun Sung Kim
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
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11
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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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12
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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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13
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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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14
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Stepanova AV, Mironov AV, Bogach AV, Azarevich AN, Presniakov IA, Sobolev AV, Pankratov DA, Zayakhanov VA, Starchikov SS, Verchenko VY, Shevelkov AV. Bulk ferromagnetism in cleavable van der Waals telluride NbFeTe 2. Chem Commun (Camb) 2024; 60:5518-5521. [PMID: 38693880 DOI: 10.1039/d4cc01160k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
A van der Waals telluride, NbFeTe2, has been synthesized using chemical vapor transport reactions. The optimized synthetic conditions yield high-quality single crystals with a novel monoclinic crystal structure. Monoclinic NbFeTe2 demonstrates a (100) cleavage plane, bulk ferromagnetism below 87 K, and a metallic ground state-the necessary prerequisites for needed spintronics technologies.
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Affiliation(s)
- Anna V Stepanova
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Andrei V Mironov
- 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
| | - Andrey N Azarevich
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Igor A Presniakov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
- MSU-BIT University, Shenzhen, 517182 Guangdong Province, P. R. China
| | - Alexey V Sobolev
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
- MSU-BIT University, Shenzhen, 517182 Guangdong Province, P. R. China
| | - Denis A Pankratov
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | | | | | - Valeriy Yu Verchenko
- 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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15
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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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16
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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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17
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Ji Y, Yang S, Ahn HB, Moon KW, Ju TS, Im MY, Han HS, Lee J, Park SY, Lee C, Kim KJ, Hwang C. Direct Observation of Room-Temperature Magnetic Skyrmion Motion Driven by Ultra-Low Current Density in Van Der Waals Ferromagnets. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2312013. [PMID: 38270245 DOI: 10.1002/adma.202312013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 01/05/2024] [Indexed: 01/26/2024]
Abstract
The recent discovery of room-temperature ferromagnetism in 2D van der Waals (vdW) materials, such as Fe3GaTe2 (FGaT), has garnered significant interest in offering a robust platform for 2D spintronic applications. Various fundamental operations essential for the realization of 2D spintronics devices are experimentally confirmed using these materials at room temperature, such as current-induced magnetization switching or tunneling magnetoresistance. Nevertheless, the potential applications of magnetic skyrmions in FGaT systems at room temperature remain unexplored. In this work, the current-induced generation of magnetic skyrmions in FGaT flakes employing high-resolution magnetic transmission soft X-ray microscopy is introduced, supported by a feasible mechanism based on thermal effects. Furthermore, direct observation of the current-induced magnetic skyrmion motion at room temperature in FGaT flakes is presented with ultra-low threshold current density. This work highlights the potential of FGaT as a foundation for room-temperature-operating 2D skyrmion device applications.
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Affiliation(s)
- Yubin Ji
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Seungmo Yang
- Quantum Spin Team, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - Hyo-Bin Ahn
- SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Kyoung-Woong Moon
- Quantum Spin Team, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - Tae-Seong Ju
- Quantum Spin Team, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - Mi-Young Im
- Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Hee-Sung Han
- Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Materials Science and Engineering, Korea National University of Transportation, Chungju, 27469, Republic of Korea
| | - Jisung Lee
- Center for scientific instrumentation, Korea Basic Science Institute, Daejeon, 34133, Republic of Korea
| | - Seung-Young Park
- Center for scientific instrumentation, Korea Basic Science Institute, Daejeon, 34133, Republic of Korea
| | - Changgu Lee
- School of Mechanical Engineering, Sungykunkwan University, Suwon, 16419, Republic of Korea
| | - Kab-Jin Kim
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Chanyong Hwang
- Quantum Spin Team, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
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18
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Wang M, Zhu K, Lei B, Deng Y, Hu T, Song D, Du H, Tian M, Xiang Z, Wu T, Chen X. Layer-Number-Dependent Magnetism in the Co-Doped van der Waals Ferromagnet Fe 3GaTe 2. NANO LETTERS 2024; 24:4141-4149. [PMID: 38536947 DOI: 10.1021/acs.nanolett.3c05148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Recently, van der Waals (vdW) antiferromagnets have been proposed to be crucial for spintronics due to their favorable properties compared to ferromagnets, including robustness against magnetic perturbation and high frequencies of spin dynamics. High-performance and energy-efficient spin functionalities often depend on the current-driven manipulation and detection of spin states, highlighting the significance of two-dimensional metallic antiferromagnets, which have not been much explored due to the lack of suitable materials. Here, we report a new metallic vdW antiferromagnet obtained from the ferromagnet Fe3GaTe2 by cobalt (Co) doping. Through the layer-number-dependent Hall resistance and magnetoresistance measurements, an evident odd-even layer-number effect has been observed in its few-layered flakes, suggesting that it could host an A-type antiferromagnetic structure. This peculiar layer-number-dependent magnetism in Co-doped Fe3GaTe2 helps unravel the complex magnetic structures in such doped vdW magnets, and our finding will enrich material candidates and spin functionalities for spintronic applications.
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Affiliation(s)
- Mingjie Wang
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Kejia Zhu
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Bin Lei
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Yazhou Deng
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Tao Hu
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Dongsheng Song
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Haifeng Du
- Anhui Province Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China
| | - Mingliang Tian
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Ziji Xiang
- 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
| | - Tao Wu
- 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
| | - Xianhui Chen
- 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
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei, Anhui 230026, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
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19
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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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20
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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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21
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Zhang Y, Zhang S, Jia M, Wang T, Guan L, Tao J. Prediction of intrinsic room-temperature ferromagnetism in two-dimensional CrInX 2 (X = S, Se, Te) monolayers. Phys Chem Chem Phys 2024; 26:8183-8194. [PMID: 38380595 DOI: 10.1039/d3cp06010a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Herein, using density functional theory, novel two-dimensional (2D) CrInX2 (X = S, Se, Te) structures are predicted to be practical ferromagnetic (FM) semiconductors. Phonon vibrations and molecular dynamics simulations verified their structural and thermodynamic stability. Sizable fully spin-polarized band gaps of 1.03 and 0.69 eV are found for CrInS2 and CrInSe2, while CrInTe2 exhibits half-metallic band nature (at 0 K with a perfect lattice). The high magnetic anisotropy energies are responsible for their long-range spin polarization. The Curie temperatures (Tc) are estimated to be 347, 397 and 447 K for CrInS2, CrInSe2 and CrInTe2, respectively, all well above the room-temperature. The high Tc originates from unusual FM direct exchange, the efficient super-exchange coupling between neighboring Cr eg-orbitals with zero virtual exchange gaps and the presence of dual Cr-X-Cr super-exchange channels. Our systematic study of the CrInX2 monolayer suggests that it could be a promising material for spintronics applications.
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Affiliation(s)
- Yunfei Zhang
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132, China.
| | - Shuo Zhang
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132, China.
| | - Minghao Jia
- School of Sciences, Hebei University of Technology, Tianjin 300401, China.
| | - Tian Wang
- School of Sciences, Hebei University of Technology, Tianjin 300401, China.
| | - Lixiu Guan
- School of Sciences, Hebei University of Technology, Tianjin 300401, China.
| | - Junguang Tao
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132, China.
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22
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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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23
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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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24
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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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25
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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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26
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Gopi AK, Srivastava AK, Sharma AK, Chakraborty A, Das S, Deniz H, Ernst A, Hazra BK, Meyerheim HL, Parkin SSP. Thickness-Tunable Zoology of Magnetic Spin Textures Observed in Fe 5GeTe 2. ACS NANO 2024. [PMID: 38315563 PMCID: PMC10883052 DOI: 10.1021/acsnano.3c09602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
The family of two-dimensional (2D) van der Waals (vdW) materials provides a playground for tuning structural and magnetic interactions to create a wide variety of spin textures. Of particular interest is the ferromagnetic compound Fe5GeTe2 that we show displays a range of complex spin textures as well as complex crystal structures. Here, using a high-brailliance laboratory X-ray source, we show that the majority (1 × 1) Fe5GeTe2 (FGT5) phase exhibits a structure that was previously considered as being centrosymmetric but rather lacks inversion symmetry. In addition, FGT5 exhibits a minority phase that exhibits a long-range ordered (√3 × √3)-R30° superstructure. This superstructure is highly interesting in that it is innately 2D without any lattice periodicity perpendicular to the vdW layers, and furthermore, the superstructure is a result of ordered Te vacancies in one of the topmost layers of the FGT5 sheets rather than being a result of vertical Fe ordering as earlier suggested. We show, from direct real-space magnetic imaging, evidence for three distinct magnetic ground states in lamellae of FGT5 that are stabilized with increasing lamella thickness, namely, a multidomain state, a stripe phase, and an unusual fractal state. In the stripe phase we also observe unconventional type-I and type-II bubbles where the spin texture in the central region of the bubbles is nonuniform, unlike conventional bubbles. In addition, we find a bobber or a cocoon-like spin texture in thick (∼170 μm) FGT5 that emerges from the fractal state in the presence of a magnetic field. Among all the 2D vdW magnets we have thus demonstrated that FGT5 hosts perhaps the richest variety of magnetic phases that, thereby, make it a highly interesting platform for the subtle tuning of magnetic interactions.
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Affiliation(s)
- Ajesh K Gopi
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Abhay K Srivastava
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Ankit K Sharma
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Anirban Chakraborty
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Souvik Das
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Hakan Deniz
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Arthur Ernst
- Johannes Kepler University, Altenbergerstraβe 69, Linz 4040, Austria
| | - Binoy K Hazra
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Holger L Meyerheim
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
| | - Stuart S P Parkin
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle (Saale) D-06120, Germany
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27
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Guillet T, Galceran R, Sierra JF, Belarre FJ, Ballesteros B, Costache MV, Dosenovic D, Okuno H, Marty A, Jamet M, Bonell F, Valenzuela SO. Spin-Orbit Torques and Magnetization Switching in (Bi,Sb) 2Te 3/Fe 3GeTe 2 Heterostructures Grown by Molecular Beam Epitaxy. NANO LETTERS 2024; 24:822-828. [PMID: 38263950 DOI: 10.1021/acs.nanolett.3c03291] [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
Topological insulators (TIs) hold promise for manipulating the magnetization of a ferromagnet (FM) through the spin-orbit torque (SOT) mechanism. However, integrating TIs with conventional FMs often leads to significant device-to-device variations and a broad distribution of SOT magnitudes. In this work, we present a scalable approach to grow a full van der Waals FM/TI heterostructure by molecular beam epitaxy, combining the charge-compensated TI (Bi,Sb)2Te3 with 2D FM Fe3GeTe2 (FGT). Harmonic magnetotransport measurements reveal that the SOT efficiency exhibits a non-monotonic temperature dependence and experiences a substantial enhancement with a reduction of the FGT thickness to 2 monolayers. Our study further demonstrates that the magnetization of ultrathin FGT films can be switched with a current density of Jc ∼ 1010 A/m2, with minimal device-to-device variations compared to previous investigations involving traditional FMs.
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Affiliation(s)
- Thomas Guillet
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Regina Galceran
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Juan F Sierra
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Francisco J Belarre
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Belén Ballesteros
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Marius V Costache
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | | | - Hanako Okuno
- Univ. Grenoble Alpes, CEA, IRIG-MEM, 38000 Grenoble, France
| | - Alain Marty
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000 Grenoble, France
| | - Matthieu Jamet
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000 Grenoble, France
| | - Frédéric Bonell
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000 Grenoble, France
| | - Sergio O Valenzuela
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08070 Barcelona, Spain
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28
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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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29
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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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30
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Lee JE, Yan S, Oh S, Hwang J, Denlinger JD, Hwang C, Lei H, Mo SK, Park SY, Ryu H. Electronic Structure of Above-Room-Temperature van der Waals Ferromagnet Fe 3GaTe 2. NANO LETTERS 2023; 23:11526-11532. [PMID: 38079244 DOI: 10.1021/acs.nanolett.3c03203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Fe3GaTe2, a recently discovered van der Waals ferromagnet, demonstrates intrinsic ferromagnetism above room temperature, necessitating a comprehensive investigation of the microscopic origins of its high Curie temperature (TC). In this study, we reveal the electronic structure of Fe3GaTe2 in its ferromagnetic ground state using angle-resolved photoemission spectroscopy and density functional theory calculations. Our results establish a consistent correspondence between the measured band structure and theoretical calculations, underscoring the significant contributions of the Heisenberg exchange interaction (Jex) and magnetic anisotropy energy to the development of the high-TC ferromagnetic ordering in Fe3GaTe2. Intriguingly, we observe substantial modifications to these crucial driving factors through doping, which we attribute to alterations in multiple spin-splitting bands near the Fermi level. These findings provide valuable insights into the underlying electronic structure and its correlation with the emergence of high-TC ferromagnetic ordering in Fe3GaTe2.
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Affiliation(s)
- Ji-Eun Lee
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Max Planck POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Shaohua Yan
- Beijing Key Laboratory of Optoelectronic Functional Materials MicroNano Devices, Department of Physics, 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
| | - Sehoon Oh
- Department of Physics and Origin of Matter and Evolution of Galaxies (OMEG) Institute, Soongsil University, Seoul 06978, Korea
| | - Jinwoong Hwang
- Department of Physics, Kangwon National University, Chuncheon 24341, Korea
| | - Jonathan D Denlinger
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Choongyu Hwang
- Department of Physics, Pusan National University, Busan 46241, Korea
- Quantum Matter Core Facility, Pusan National University, Busan 46241, Korea
| | - Hechang Lei
- Beijing Key Laboratory of Optoelectronic Functional Materials MicroNano Devices, Department of Physics, 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
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Se Young Park
- Department of Physics and Origin of Matter and Evolution of Galaxies (OMEG) Institute, Soongsil University, Seoul 06978, Korea
| | - Hyejin Ryu
- Center for Spintronics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
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31
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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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32
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Schulz F, Litzius K, Powalla L, Birch MT, Gallardo RA, Satheesh S, Weigand M, Scholz T, Lotsch BV, Schütz G, Burghard M, Wintz S. Direct Observation of Propagating Spin Waves in the 2D van der Waals Ferromagnet Fe 5GeTe 2. NANO LETTERS 2023; 23:10126-10131. [PMID: 37955345 PMCID: PMC10683057 DOI: 10.1021/acs.nanolett.3c02212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 11/01/2023] [Accepted: 11/03/2023] [Indexed: 11/14/2023]
Abstract
Magnetism in reduced dimensionalities is of great fundamental interest while also providing perspectives for applications of materials with novel functionalities. In particular, spin dynamics in two dimensions (2D) have become a focus of recent research. Here, we report the observation of coherent propagating spin-wave dynamics in a ∼30 nm thick flake of 2D van der Waals ferromagnet Fe5GeTe2 using X-ray microscopy. Both phase and amplitude information were obtained by direct imaging below TC for frequencies from 2.77 to 3.84 GHz, and the corresponding spin-wave wavelengths were measured to be between 1.5 and 0.5 μm. Thus, parts of the magnonic dispersion relation were determined despite a relatively high magnetic damping of the material. Numerically solving an analytic multilayer model allowed us to corroborate the experimental dispersion relation and predict the influence of changes in the saturation magnetization or interlayer coupling, which could be exploited in future applications by temperature control or stacking of 2D-heterostructures.
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Affiliation(s)
- Frank Schulz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
| | - Kai Litzius
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
- Universität
Augsburg, D-86159 Augsburg, Germany
| | - Lukas Powalla
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Max T. Birch
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
- RIKEN
Center for Emergent Matter Science, JP-351-0198 Wako, Japan
| | - Rodolfo A. Gallardo
- Universidad
Técnica Federico Santa María, Avenida España 1680, 2390123 Valparaiso, Chile
| | - Sayooj Satheesh
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Markus Weigand
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
| | - Tanja Scholz
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Bettina V. Lotsch
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Gisela Schütz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
| | - Marko Burghard
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Sebastian Wintz
- Max
Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
- Helmholtz-Zentrum
Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
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33
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Liu S, Malik IA, Zhang VL, Yu T. Lightning the Spin: Harnessing the Potential of 2D Magnets in Opto-Spintronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2306920. [PMID: 37905890 DOI: 10.1002/adma.202306920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/20/2023] [Indexed: 11/02/2023]
Abstract
Since the emergence of 2D magnets in 2017, the diversity of these materials has greatly expanded. Their 2D nature (atomic-scale thickness) endows these magnets with strong magnetic anisotropy, layer-dependent and switchable magnetic order, and quantum-confined quasiparticles, which distinguish them from conventional 3D magnetic materials. Moreover, the 2D geometry facilitates light incidence for opto-spintronic applications and potential on-chip integration. In analogy to optoelectronics based on optical-electronic interactions, opto-spintronics use light-spin interactions to process spin information stored in the solid state. In this review, opto-spintronics is divided into three types with respect to the wavelengths of radiation interacting with 2D magnets: 1) GHz (microwave) to THz (mid-infrared), 2) visible, and 3) UV to X-rays. It is focused on the recent research advancements on the newly discovered mechanisms of light-spin interactions in 2D magnets and introduces the potential design of novel opto-spintronic applications based on these interactions.
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Affiliation(s)
- Sheng Liu
- School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
| | | | - Vanessa Li Zhang
- School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
| | - Ting Yu
- School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
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34
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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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35
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Man P, Huang L, Zhao J, Ly TH. Ferroic Phases in Two-Dimensional Materials. Chem Rev 2023; 123:10990-11046. [PMID: 37672768 DOI: 10.1021/acs.chemrev.3c00170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
Two-dimensional (2D) ferroics, namely ferroelectric, ferromagnetic, and ferroelastic materials, are attracting rising interest due to their fascinating physical properties and promising functional applications. A variety of 2D ferroic phases, as well as 2D multiferroics and the novel 2D ferrovalleytronics/ferrotoroidics, have been recently predicted by theory, even down to the single atomic layers. Meanwhile, some of them have already been experimentally verified. In addition to the intrinsic 2D ferroics, appropriate stacking, doping, and defects can also artificially regulate the ferroic phases of 2D materials. Correspondingly, ferroic ordering in 2D materials exhibits enormous potential for future high density memory devices, energy conversion devices, and sensing devices, among other applications. In this paper, the recent research progresses on 2D ferroic phases are comprehensively reviewed, with emphasis on chemistry and structural origin of the ferroic properties. In addition, the promising applications of the 2D ferroics for information storage, optoelectronics, and sensing are also briefly discussed. Finally, we envisioned a few possible pathways for the future 2D ferroics research and development. This comprehensive overview on the 2D ferroic phases can provide an atlas for this field and facilitate further exploration of the intriguing new materials and physical phenomena, which will generate tremendous impact on future functional materials and devices.
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Affiliation(s)
- Ping Man
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, P. R. China
| | - Lingli Huang
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, P. R. China
| | - Jiong Zhao
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, P. R. China
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, P. R. China
| | - Thuc Hue Ly
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, P. R. China
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
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36
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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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37
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Högen M, Fujita R, Tan AKC, Geim A, Pitts M, Li Z, Guo Y, Stefan L, Hesjedal T, Atatüre M. Imaging Nucleation and Propagation of Pinned Domains in Few-Layer Fe 5-xGeTe 2. ACS NANO 2023; 17:16879-16885. [PMID: 37642321 PMCID: PMC10510720 DOI: 10.1021/acsnano.3c03825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/23/2023] [Indexed: 08/31/2023]
Abstract
Engineering nontrivial spin textures in magnetic van der Waals materials is highly desirable for spintronic applications based on hybrid heterostructures. The recent observation of labyrinth and bubble domains in the near room-temperature ferromagnet Fe5-xGeTe2 down to a bilayer thickness was thus a significant advancement toward van der Waals-based many-body physics. However, the physical mechanism responsible for stabilizing these domains remains unclear and requires further investigation. Here, we combine cryogenic scanning diamond quantum magnetometry and field reversal techniques to elucidate the high-field propagation and nucleation of bubble domains in trilayer Fe5-xGeTe2. We provide evidence of pinning-induced nucleation of magnetic bubbles and further show an unexpectedly high layer-dependent coercive field. These measurements can be easily extended to a wide range of magnetic materials to provide valuable nanoscale insight into domain processes critical for spintronic applications.
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Affiliation(s)
- Michael Högen
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, Cambridge, CB3 0HE, United
Kingdom
| | - Ryuji Fujita
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Oxford, OX1 3PU, United
Kingdom
| | - Anthony K. C. Tan
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, Cambridge, CB3 0HE, United
Kingdom
- Department
of Physics, Imperial College, London, SW7 2AZ, United Kingdom
| | - Alexandra Geim
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, Cambridge, CB3 0HE, United
Kingdom
| | - Michael Pitts
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, Cambridge, CB3 0HE, United
Kingdom
| | - 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
| | - Lucio Stefan
- Center
for Hybrid Quantum Networks (Hy-Q), Niels
Bohr Institute, 2100 Copenhagen, Denmark
| | - Thorsten Hesjedal
- Clarendon
Laboratory, Department of Physics, University
of Oxford, Oxford, OX1 3PU, United
Kingdom
| | - Mete Atatüre
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, Cambridge, CB3 0HE, United
Kingdom
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38
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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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39
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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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40
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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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41
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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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42
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Meisenheimer P, Zhang H, Raftrey D, Chen X, Shao YT, Chan YT, Yalisove R, Chen R, Yao J, Scott MC, Wu W, Muller DA, Fischer P, Birgeneau RJ, Ramesh R. Ordering of room-temperature magnetic skyrmions in a polar van der Waals magnet. Nat Commun 2023; 14:3744. [PMID: 37353526 DOI: 10.1038/s41467-023-39442-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 06/13/2023] [Indexed: 06/25/2023] Open
Abstract
Control and understanding of ensembles of skyrmions is important for realization of future technologies. In particular, the order-disorder transition associated with the 2D lattice of magnetic skyrmions can have significant implications for transport and other dynamic functionalities. To date, skyrmion ensembles have been primarily studied in bulk crystals, or as isolated skyrmions in thin film devices. Here, we investigate the condensation of the skyrmion phase at room temperature and zero field in a polar, van der Waals magnet. We demonstrate that we can engineer an ordered skyrmion crystal through structural confinement on the μm scale, showing control over this order-disorder transition on scales relevant for device applications.
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Affiliation(s)
- Peter Meisenheimer
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
| | - Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
| | - David Raftrey
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Santa Cruz, CA, USA
| | - Xiang Chen
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Yu-Tsun Shao
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Ying-Ting Chan
- Department of Physics, Rutgers University, New Brunswick, NJ, USA
| | - Reed Yalisove
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Rui Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Jie Yao
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Mary C Scott
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Weida Wu
- Department of Physics, Rutgers University, New Brunswick, NJ, USA
| | - David A Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Peter Fischer
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Santa Cruz, CA, USA
| | - Robert J Birgeneau
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
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43
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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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44
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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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45
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Casas BW, Li Y, Moon A, Xin Y, McKeever C, Macy J, Petford-Long AK, Phatak CM, Santos EJG, Choi ES, Balicas L. Coexistence of Merons with Skyrmions in the Centrosymmetric Van Der Waals Ferromagnet Fe 5- x GeTe 2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2212087. [PMID: 36780298 DOI: 10.1002/adma.202212087] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 02/02/2023] [Indexed: 05/17/2023]
Abstract
Fe5- x GeTe2 is a centrosymmetric, layered van der Waals (vdW) ferromagnet that displays Curie temperatures Tc (270-330 K) that are within the useful range for spintronic applications. However, little is known about the interplay between its topological spin textures (e.g., merons, skyrmions) with technologically relevant transport properties such as the topological Hall effect (THE) or topological thermal transport. Here, via high-resolution Lorentz transmission electron microscopy, it is shown that merons and anti-meron pairs coexist with Néel skyrmions in Fe5- x GeTe2 over a wide range of temperatures and probe their effects on thermal and electrical transport. A THE is detected, even at room T, that senses merons at higher T's, as well as their coexistence with skyrmions as T is lowered, indicating an on-demand thermally driven formation of either type of spin texture. Remarkably, an unconventional THE is also observed in absence of Lorentz force, and it is attributed to the interaction between charge carriers and magnetic field-induced chiral spin textures. These results expose Fe5-x GeTe2 as a promising candidate for the development of applications in skyrmionics/meronics due to the interplay between distinct but coexisting topological magnetic textures and unconventional transport of charge/heat carriers.
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Affiliation(s)
- Brian W Casas
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Yue Li
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Alex Moon
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
- Department of Physics, Florida State University, Tallahassee, FL, 32306, USA
| | - Yan Xin
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Conor McKeever
- Institute for Condensed Matter and Complex Systems, School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, UK
| | - Juan Macy
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
- Department of Physics, Florida State University, Tallahassee, FL, 32306, USA
| | - Amanda K Petford-Long
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Charudatta M Phatak
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Elton J G Santos
- Institute for Condensed Matter and Complex Systems, School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, UK
- Higgs Centre for Theoretical Physics, The University of Edinburgh, Edinburgh, EH9 3FD, UK
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Basque Country, Spain
| | - Eun Sang Choi
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
- Department of Physics, Florida State University, Tallahassee, FL, 32306, USA
| | - Luis Balicas
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
- Department of Physics, Florida State University, Tallahassee, FL, 32306, USA
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46
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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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47
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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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48
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Zhao Z, Fang Z, Han X, Yang S, Zhou C, Zeng Y, Zhang B, Li W, Wang Z, Zhang Y, Zhou J, Zhou J, Ye Y, Hou X, Zhao X, Gao S, Hou Y. A general thermodynamics-triggered competitive growth model to guide the synthesis of two-dimensional nonlayered materials. Nat Commun 2023; 14:958. [PMID: 36810290 PMCID: PMC9944324 DOI: 10.1038/s41467-023-36619-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 02/08/2023] [Indexed: 02/23/2023] Open
Abstract
Two-dimensional (2D) nonlayered materials have recently provoked a surge of interest due to their abundant species and attractive properties with promising applications in catalysis, nanoelectronics, and spintronics. However, their 2D anisotropic growth still faces considerable challenges and lacks systematic theoretical guidance. Here, we propose a general thermodynamics-triggered competitive growth (TTCG) model providing a multivariate quantitative criterion to predict and guide 2D nonlayered materials growth. Based on this model, we design a universal hydrate-assisted chemical vapor deposition strategy for the controllable synthesis of various 2D nonlayered transition metal oxides. Four unique phases of iron oxides with distinct topological structures have also been selectively grown. More importantly, ultra-thin oxides display high-temperature magnetic ordering and large coercivity. MnxFeyCo3-x-yO4 alloy is also demonstrated to be a promising room-temperature magnetic semiconductor. Our work sheds light on the synthesis of 2D nonlayered materials and promotes their application for room-temperature spintronic devices.
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Affiliation(s)
- Zijing Zhao
- grid.11135.370000 0001 2256 9319School of Materials Science and Engineering, Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing, 100871 China ,grid.11135.370000 0001 2256 9319Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871 China
| | - Zhi Fang
- grid.11135.370000 0001 2256 9319School of Materials Science and Engineering, Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing, 100871 China
| | - Xiaocang Han
- grid.11135.370000 0001 2256 9319School of Materials Science and Engineering, Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing, 100871 China
| | - Shiqi Yang
- grid.11135.370000 0001 2256 9319State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871 China
| | - Cong Zhou
- grid.43169.390000 0001 0599 1243Center for Alloy Innovation and Design, State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, 710049 China
| | - Yi Zeng
- grid.11135.370000 0001 2256 9319School of Materials Science and Engineering, Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing, 100871 China
| | - Biao Zhang
- grid.11135.370000 0001 2256 9319School of Materials Science and Engineering, Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing, 100871 China
| | - Wei Li
- grid.11135.370000 0001 2256 9319School of Materials Science and Engineering, Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing, 100871 China
| | - Zhan Wang
- grid.9227.e0000000119573309Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 China
| | - Ying Zhang
- grid.9227.e0000000119573309Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 China
| | - Jian Zhou
- grid.43169.390000 0001 0599 1243Center for Alloy Innovation and Design, State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, 710049 China
| | - Jiadong Zhou
- grid.43555.320000 0000 8841 6246Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, School of Physics, Beijing Institute of Technology, Beijing, 100081 China
| | - Yu Ye
- grid.11135.370000 0001 2256 9319State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871 China
| | - Xinmei Hou
- grid.69775.3a0000 0004 0369 0705Innovation Research Institute for Carbon Neutrality, University of Science and Technology Beijing, Beijing, 100083 China
| | - Xiaoxu Zhao
- School of Materials Science and Engineering, Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing, 100871, China.
| | - Song Gao
- grid.79703.3a0000 0004 1764 3838Institute of Spin-X Science and Technology, South China University of Technology, Guangzhou, 510641 China
| | - Yanglong Hou
- School of Materials Science and Engineering, Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing, 100871, China. .,Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China.
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49
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He X, Zhang C, Zheng D, Li P, Xiao JQ, Zhang X. Nonlocal Spin Valves Based on Graphene/Fe 3GeTe 2 van der Waals Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2023; 15:9649-9655. [PMID: 36753695 PMCID: PMC9951179 DOI: 10.1021/acsami.2c21918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
With recent advances in two-dimensional (2D) ferromagnets with enhanced Curie temperatures, it is possible to develop all-2D spintronic devices with high-quality interfaces using 2D ferromagnets. In this study, we have successfully fabricated nonlocal spin valves with Fe3GeTe2 (FGT) as the spin source and detector and multilayer graphene as the spin transport channel. The nonlocal spin transport signal was found to strongly depend on temperature and disappear at a temperature below the Curie temperature of the FGT flakes, which stemmed from the temperature-dependent ferromagnetism of FGT. The spin injection efficiency was estimated to be about 1%, close to that of conventional nonlocal spin valves with transparent contacts between ferromagnetic electrodes and the graphene channel. In addition, the spin transport signal was found to depend on the direction of the magnetic field and the magnitude of the current, which was due to the strong perpendicular magnetic anisotropy of FGT and the thermal effect, respectively. Our results provide opportunities to extend the applications of van der Waals heterostructures in spintronic devices.
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Affiliation(s)
- Xin He
- Physical
Science and Engineering Division, King Abdullah
University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Chenhui Zhang
- Physical
Science and Engineering Division, King Abdullah
University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Dongxing Zheng
- Physical
Science and Engineering Division, King Abdullah
University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Peng Li
- State
Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of
China, Chengdu 610054, China
| | - John Q. Xiao
- Department
of Physics and Astronomy, University of
Delaware, Newark, Delaware 19716, United States
| | - Xixiang Zhang
- Physical
Science and Engineering Division, King Abdullah
University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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50
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Han J, Lv C, Yang W, Wang X, Wei G, Zhao W, Lin X. Large tunneling magnetoresistance in van der Waals magnetic tunnel junctions based on FeCl 2 films with interlayer antiferromagnetic couplings. NANOSCALE 2023; 15:2067-2078. [PMID: 36594492 DOI: 10.1039/d2nr05684d] [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
Antiferromagnets (AFMs) are some of the most promising candidates for next-generation magnetic memory technology owing to their advantages over conventional ferromagnets (FMs), such as zero stray field and THz-range magnetic resonance frequency. Motivated by the recent synthesis of FeCl2 films with interlayer AFM and intralayer FM couplings, we investigated the magnetic properties of few-layer FeCl2 and the spin-dependent transmissions of graphite/bilayer FeCl2/graphite and Au/n-layer FeCl2/Au magnetic tunnel junctions (MTJs) using first-principles calculations combined with the nonequilibrium Green's function. The interlayer AFM coupling of FeCl2 is certified to be stable and independent of the stacking orders and relative displacement between layers. Furthermore, based on the Au electrode with better conductive performance than the graphite electrode and monolayer 1T-FeCl2 with complete spin polarization, high Curie temperature and large magnetic anisotropic energy, a high tunnel magnetoresistance (TMR) ratio of 2.7 × 103% is achieved in Au/bilayer FeCl2/Au MTJs at zero bias and it increases with different layers of FeCl2 (n = 2-10). These excellent spin transport properties of Au/n-layer FeCl2/Au MTJs based on two-dimensional (2D) AFM barriers with out-of-plane magnetization directions suggest their great potential for application in high-reliability, high-speed and high-density spintronic devices.
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Affiliation(s)
- Jiangchao Han
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China.
| | - Chen Lv
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China.
| | - Wei Yang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China.
| | - Xinhe Wang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China.
| | - Guodong Wei
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China.
| | - Weisheng Zhao
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China.
| | - Xiaoyang Lin
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China.
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