1
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Kim D, Ain QU, Nam Y, Yu J, Lee S, Chang J, Kim K, Shim W, Kim D, Je S, Min B, Rhim SH, Choe S. Sign Reversal of Spin-Transfer Torques. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2309467. [PMID: 38626368 PMCID: PMC11304287 DOI: 10.1002/advs.202309467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 03/14/2024] [Indexed: 04/18/2024]
Abstract
Spin-transfer torque (STT) and spin-orbit torque (SOT) form the core of spintronics, allowing for the control of magnetization through electric currents. While the sign of SOT can be manipulated through material and structural engineering, it is conventionally understood that STT lacks a degree of freedom in its sign. However, this study presents the first demonstration of manipulating the STT sign by engineering heavy metals adjacent to magnetic materials in magnetic heterostructures. Spin torques are quantified through magnetic domain-wall speed measurements, and subsequently, both STT and SOT are systematically extracted from these measurements. The results unequivocally show that the sign of STT can be either positive or negative, depending on the materials adjacent to the magnetic layers. Specifically, Pd/Co/Pd films exhibit positive STT, while Pt/Co/Pt films manifest negative STT. First-principle calculations further confirm that the sign reversal of STT originates from the sign reversal of spin polarization of conduction electrons.
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Affiliation(s)
- Dae‐Yun Kim
- Center for SpintronicsKorea Institute of Science and Technology (KIST)Seoul02792Republic of Korea
- Samsung Advanced Institute of Technology (SAIT)Suwon16678Republic of Korea
| | - Qurat ul Ain
- Department of PhysicsUniversity of UlsanUlsan44610Republic of Korea
- Materials Science Lab, Department of PhysicsQuaid‐I‐Azam UniversityIslamabad45320Pakistan
| | - Yune‐Seok Nam
- Department of Physics and Astronomy and Institute of Applied PhysicsSeoul National UniversitySeoul08826Republic of Korea
| | - Ji‐Sung Yu
- Department of Physics and Astronomy and Institute of Applied PhysicsSeoul National UniversitySeoul08826Republic of Korea
| | - Seong‐Hyub Lee
- Department of Physics and Astronomy and Institute of Applied PhysicsSeoul National UniversitySeoul08826Republic of Korea
| | - Jun‐Young Chang
- Department of Physics and Astronomy and Institute of Applied PhysicsSeoul National UniversitySeoul08826Republic of Korea
| | - Kitae Kim
- Department of Physics and Astronomy and Institute of Applied PhysicsSeoul National UniversitySeoul08826Republic of Korea
| | - Woo‐Young Shim
- Department of Physics and Astronomy and Institute of Applied PhysicsSeoul National UniversitySeoul08826Republic of Korea
| | - Duck‐Ho Kim
- Center for SpintronicsKorea Institute of Science and Technology (KIST)Seoul02792Republic of Korea
| | - Soong‐Geun Je
- Department of PhysicsChonnam National UniversityGwangju61186Republic of Korea
| | - Byoung‐Chul Min
- Center for SpintronicsKorea Institute of Science and Technology (KIST)Seoul02792Republic of Korea
| | - Sonny H. Rhim
- Department of PhysicsUniversity of UlsanUlsan44610Republic of Korea
| | - Sug‐Bong Choe
- Department of Physics and Astronomy and Institute of Applied PhysicsSeoul National UniversitySeoul08826Republic of Korea
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2
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Wang J, Huang J, Kaplan D, Zhou X, Tan C, Zhang J, Jin G, Cong X, Zhu Y, Gao X, Liang Y, Zuo H, Zhu Z, Zhu R, Stern A, Liu H, Gao P, Yan B, Yuan H, Peng H. Even-integer quantum Hall effect in an oxide caused by a hidden Rashba effect. NATURE NANOTECHNOLOGY 2024:10.1038/s41565-024-01732-z. [PMID: 39039120 DOI: 10.1038/s41565-024-01732-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 06/28/2024] [Indexed: 07/24/2024]
Abstract
In the presence of a high magnetic field, quantum Hall systems usually host both even- and odd-integer quantized states because of lifted band degeneracies. Selective control of these quantized states is challenging but essential to understand the exotic ground states and manipulate the spin textures. Here we demonstrate the quantum Hall effect in Bi2O2Se thin films. In magnetic fields as high as 50 T, we observe only even-integer quantum Hall states, but there is no sign of odd-integer states. However, when reducing the thickness of the epitaxial Bi2O2Se film to one unit cell, we observe both odd- and even-integer states in this Janus (asymmetric) film grown on SrTiO3. By means of a Rashba bilayer model based on the ab initio band structures of Bi2O2Se thin films, we can ascribe the only even-integer states in thicker films to the hidden Rasbha effect, where the local inversion-symmetry breaking in two sectors of the [Bi2O2]2+ layer yields opposite Rashba spin polarizations, which compensate with each other. In the one-unit-cell Bi2O2Se film grown on SrTiO3, the asymmetry introduced by the top surface and bottom interface induces a net polar field. The resulting global Rashba effect lifts the band degeneracies present in the symmetric case of thicker films.
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Affiliation(s)
- Jingyue Wang
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Junwei Huang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing, China
| | - Daniel Kaplan
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
- Center for Materials Theory, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
| | - Xuehan Zhou
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Congwei Tan
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Jing Zhang
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan, China
| | - Gangjian Jin
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan, China
| | - Xuzhong Cong
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Yongchao Zhu
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Xiaoyin Gao
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Yan Liang
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Huakun Zuo
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan, China
| | - Zengwei Zhu
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan, China
| | - Ruixue Zhu
- International Center for Quantum Materials and Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Ady Stern
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Hongtao Liu
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Peng Gao
- International Center for Quantum Materials and Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Binghai Yan
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel.
| | - Hongtao Yuan
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing, China.
| | - Hailin Peng
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
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3
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Suresh S, Sadhu SPP, Mishra V, Paulus W, Ramachandra Rao MS. Tunable charge transport properties in non-stoichiometric SrIrO 3thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:425601. [PMID: 38981585 DOI: 10.1088/1361-648x/ad6111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 07/09/2024] [Indexed: 07/11/2024]
Abstract
Delving into the intricate interplay between spin-orbit coupling and Coulomb correlations in strongly correlated oxides, particularly perovskite compounds, has unveiled a rich landscape of exotic phenomena ranging from unconventional superconductivity to the emergence of topological phases. In this study, we have employed pulsed laser deposition technique to grow SrIrO3(SIO) thin films on SrTiO3substrates, systematically varying the oxygen content during the post-deposition annealing. X-ray photoelectron spectroscopy (XPS) provided insights into the stoichiometry and spin-orbit splitting energy of Iridium within the SIO film, while high-resolution x-ray studies meticulously examined the structural integrity of the thin films. Remarkably, our findings indicate a decrease in the metallicity of SIO thin films with reduced annealing O2partial pressure. Furthermore, we carried out magneto-transport studies on the SIO thin films, the results revealed intriguing insights into spin transport as a function of oxygen content. The tunability of the electronic band structure of SIO films with varying oxygen vacancy is correlated with the density functional theory calculations. Our findings elucidate the intricate mechanisms dictating spin transport properties in SIO thin films, offering invaluable guidance for the design and optimization of spintronic devices based on complex oxide materials. Notably, the ability to tune bandwidth by varying post-annealing oxygen partial pressure in iridate-based spintronic materials holds significant promise for advancing technological applications in the spintronics domain.
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Affiliation(s)
- Sreya Suresh
- Department of Physics, Nano Functional Materials Technology Centre, Quantum Centre of Excellence for Diamond and Emergent Materials, and Materials Science Research Centre, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Sai Pavan Prashanth Sadhu
- Department of Physics, Indian Institute of Information Technology, Design and Manufacturing, Kancheepuram, Chennai 600 127, India
| | - Vikash Mishra
- Department of Physics, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka 576 104, India
| | - Werner Paulus
- ICGM, Univ Montpellier, CNRS, ENSCM, 34000, Montpellier, France
| | - M S Ramachandra Rao
- Department of Physics, Nano Functional Materials Technology Centre, Quantum Centre of Excellence for Diamond and Emergent Materials, and Materials Science Research Centre, Indian Institute of Technology Madras, Chennai 600 036, India
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Ponet L, Di Lucente E, Marzari N. The energy landscape of magnetic materials. NPJ COMPUTATIONAL MATERIALS 2024; 10:151. [PMID: 39026599 PMCID: PMC11251989 DOI: 10.1038/s41524-024-01310-w] [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: 09/15/2023] [Accepted: 05/25/2024] [Indexed: 07/20/2024]
Abstract
Magnetic materials can display many solutions to the electronic-structure problem, corresponding to different local or global minima of the energy functional. In Hartree-Fock or density-functional theory different single-determinant solutions lead to different magnetizations, ionic oxidation states, hybridizations, and inter-site magnetic couplings. The vast majority of these states can be fingerprinted through their projection on the atomic orbitals of the magnetic ions. We have devised an approach that provides an effective control over these occupation matrices, allowing us to systematically explore the landscape of the potential energy surface. We showcase the emergence of a complex zoology of self-consistent states; even more so when semi-local density-functional theory is augmented - and typically made more accurate - by Hubbard corrections. Such extensive explorations allow to robustly identify the ground state of magnetic systems, and to assess the accuracy (or not) of current functionals and approximations.
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Affiliation(s)
- Louis Ponet
- Theory and Simulation of Materials (THEOS) and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, Lausanne, 1015 Switzerland
- Laboratory for Materials Simulations (LMS), Paul Scherrer Insititute, Villigen, 5232 Switzerland
| | - Enrico Di Lucente
- Theory and Simulation of Materials (THEOS) and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, Lausanne, 1015 Switzerland
| | - Nicola Marzari
- Theory and Simulation of Materials (THEOS) and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, Lausanne, 1015 Switzerland
- Laboratory for Materials Simulations (LMS), Paul Scherrer Insititute, Villigen, 5232 Switzerland
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5
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Aspegren M, Chergui L, Marnauza M, Debbarma R, Bengtsson J, Lehmann S, Dick KA, Reimann SM, Thelander C. Perfect Zeeman Anisotropy in Rotationally Symmetric Quantum Dots with Strong Spin-Orbit Interaction. NANO LETTERS 2024; 24:7927-7933. [PMID: 38885648 PMCID: PMC11229058 DOI: 10.1021/acs.nanolett.4c01247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 06/05/2024] [Accepted: 06/05/2024] [Indexed: 06/20/2024]
Abstract
In nanoscale structures with rotational symmetry, such as quantum rings, the orbital motion of electrons combined with a spin-orbit interaction can produce a very strong and anisotropic Zeeman effect. Since symmetry is sensitive to electric fields, ring-like geometries provide an opportunity to manipulate magnetic properties over an exceptionally wide range. In this work, we show that it is possible to form rotationally symmetric confinement potentials inside a semiconductor quantum dot, resulting in electron orbitals with large orbital angular momentum and strong spin-orbit interactions. We find complete suppression of Zeeman spin splitting for magnetic fields applied in the quantum dot plane, similar to the expected behavior of an ideal quantum ring. Spin splitting reappears as orbital interactions are activated with symmetry-breaking electric fields. For two valence electrons, representing a common basis for spin-qubits, we find that modulating the rotational symmetry may offer new prospects for realizing tunable protection and interaction of spin-orbital states.
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Affiliation(s)
- Markus Aspegren
- Solid State Physics and NanoLund, Lund University, SE-221 00 Lund, Sweden
| | - Lila Chergui
- Mathematical Physics and NanoLund, Lund University, SE-221 00 Lund, Sweden
| | - Mikelis Marnauza
- Centre for Analysis and Synthesis and NanoLund, Lund University, SE-221 00 Lund, Sweden
| | - Rousan Debbarma
- Solid State Physics and NanoLund, Lund University, SE-221 00 Lund, Sweden
| | - Jakob Bengtsson
- Mathematical Physics and NanoLund, Lund University, SE-221 00 Lund, Sweden
| | - Sebastian Lehmann
- Solid State Physics and NanoLund, Lund University, SE-221 00 Lund, Sweden
| | - Kimberly A Dick
- Centre for Analysis and Synthesis and NanoLund, Lund University, SE-221 00 Lund, Sweden
| | | | - Claes Thelander
- Solid State Physics and NanoLund, Lund University, SE-221 00 Lund, Sweden
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6
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Yin Z, Zhou B. Magnetic phase transition regulated by an interface coupling effect in CrBr 3/electride Ca 2N van der Waals heterostructures. Phys Chem Chem Phys 2024; 26:18382-18393. [PMID: 38912922 DOI: 10.1039/d4cp01407c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
Compared with ferromagnetic (FM) materials, antiferromagnetic (AFM) materials have the advantages of not generating stray fields, resisting magnetic field disturbances, and displaying ultrafast dynamics and are thus considered as ideal candidate materials for next-generation high-speed and high-density magnetic storage. In this study, a new AFM device was constructed based on density functional theory calculations through the formation of a CrBr3/Ca2N van der Waals heterostructure. The FM ground state in CrBr3 undergoes an AFM transition when combining with the electride Ca2N. In such a system, since the metal Ca atoms form the exposed layer in the electride, the heterostructure interface has a high binding energy and a large amount of charge transfer. However, for individual electron doping, the FM ground state in the CrBr3 monolayer is robust. Therefore, the main factor in magnetic phase transition is the interface orbital coupling caused by the strong binding energy. Furthermore, the interface coupling effect was revealed to be a competition between direct exchange and superexchange interactions. Additionally, different pathways of orbital hybridization cause a transition of the magnetic anisotropy from out-of-plane to in-plane. This work not only provides a feasible strategy for changing the ground state of magnetic materials on electride substrates but also brings about more possibilities for the construction and advancement of new AFM devices.
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Affiliation(s)
- Zhengyu Yin
- Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
| | - Baozeng Zhou
- Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
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7
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Wang X, Zhu X, Wu P, Li Q, Li Z, Zhang X, Liu Z, Zhang Y, Du P. Differences in Kondo Splitting of Surface Quantum Systems Induced by Two Distinct Magnetic Tips: A Joint Method of DFT and HEOM. J Phys Chem A 2024; 128:4750-4760. [PMID: 38832647 DOI: 10.1021/acs.jpca.4c02067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
The interactions between a magnetic tip and local spin impurities initiate unconventional Kondo phenomena, such as asymmetric suppression or even splitting of the Kondo peak. However, a lack of realistic theoretical models and comprehensive explanations for this phenomenon persists due to the complexity of the interactions. This research employs a joint method of density functional theory (DFT) and hierarchical equation of motion (HEOM) to simulate and contrast the modulation of the spin state and Kondo behavior in the Fe/Cu(100) system with two distinct magnetic tips. A cobalt tip, possessing a larger magnetic moment, incites greater atomic displacement of the iron atom, more notable alterations in electronic structure, and enhanced charge transfer with the environment compared with the control process utilizing a nickel tip. Furthermore, the Kondo resonance undergoes asymmetric splitting as a result of the ferromagnetic correlation between the iron atom and the magnetic tip. The Co tip's higher spin polarization results in a wider spacing between the splitting peaks. This investigation underscores the precision of the DFT + HEOM approach in predicting complex quantum phenomena and explaining the underlying physical principles. This provides valuable theoretical support for developing more sophisticated quantum regulation experiments.
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Affiliation(s)
- Xiaoli Wang
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Xinru Zhu
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Ping Wu
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Qing Li
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Zhen Li
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Xiaolei Zhang
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Zhongmin Liu
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Yuexing Zhang
- Shandong Provincial Key Laboratory of Monocrystalline Silicon Semiconductor Materials and Technology, College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, PR China
| | - Pengli Du
- College of Chemical Engineering, Qinghai University, Xining 810016, PR China
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8
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Xing J, Wu C, Li S, Chen Y, Zhang L, Xie Y, Yuan J, Zhang L. Spin Hall effect modulated by an electric field in asymmetric two-dimensional MoSiAs 2Se. Phys Chem Chem Phys 2024; 26:15539-15546. [PMID: 38756083 DOI: 10.1039/d4cp00594e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Spin current generation from charge current in nonmagnetic materials promises an energy-efficient scheme for manipulating magnetization in spintronic devices. In some asymmetric two-dimensional (2D) materials, the Rashba and valley effects coexist owing to strong spin-orbit coupling (SOC), which induces the spin Hall effect due to spin-momentum locking of both effects. Herein, we propose a new Janus structure MoSiAs2Se with both valley physics and the Rashba effect and reveal an effective way to modulate the properties of this structure. The results demonstrated that applying an external electric field is an effective means to modulating the electronic properties of MoSiAs2Se, leading to both type I-II phase transitions and semiconductor-metal phase transitions. Furthermore, the coexistence of the Rashba and valley effects in monolayer MoSiAs2Se contributes to the spin Hall effect (SHE). The magnitude and direction of spin Hall conductivity can also be manipulated with an out-of-plane electric field. Our results enrich the physics and materials of the Rashba and valley systems, opening new opportunities for the applications of 2D Janus materials in spintronic devices.
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Affiliation(s)
- Jinhui Xing
- School of Physics and Electronic Engineering, Jiangsu University, Zhenjiang 212013, China.
- Jiangsu Engineering Research Center on Quantum Perception and Intelligent Detection of Agricultural Information, Zhenjiang 212013, China
| | - Chao Wu
- School of Physics and Electronic Engineering, Jiangsu University, Zhenjiang 212013, China.
- Jiangsu Engineering Research Center on Quantum Perception and Intelligent Detection of Agricultural Information, Zhenjiang 212013, China
| | - Shiqi Li
- School of Physics and Electronic Engineering, Jiangsu University, Zhenjiang 212013, China.
- Jiangsu Engineering Research Center on Quantum Perception and Intelligent Detection of Agricultural Information, Zhenjiang 212013, China
| | - Yuanping Chen
- School of Physics and Electronic Engineering, Jiangsu University, Zhenjiang 212013, China.
- Jiangsu Engineering Research Center on Quantum Perception and Intelligent Detection of Agricultural Information, Zhenjiang 212013, China
| | - Lizhi Zhang
- National Center for Nanoscience and Technology of China, Beijing 100190, China
| | - Yuee Xie
- School of Physics and Electronic Engineering, Jiangsu University, Zhenjiang 212013, China.
- Jiangsu Engineering Research Center on Quantum Perception and Intelligent Detection of Agricultural Information, Zhenjiang 212013, China
| | - Jiaren Yuan
- School of Physics and Materials Science, Nanchang University, Nanchang 330031, China.
| | - Lichuan Zhang
- School of Physics and Electronic Engineering, Jiangsu University, Zhenjiang 212013, China.
- Jiangsu Engineering Research Center on Quantum Perception and Intelligent Detection of Agricultural Information, Zhenjiang 212013, China
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9
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Su Y, He Z, Jiang R, Zhang J. Observation of Linear Magnetoresistance in MoO 2. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:915. [PMID: 38869538 PMCID: PMC11173525 DOI: 10.3390/nano14110915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/17/2024] [Accepted: 05/21/2024] [Indexed: 06/14/2024]
Abstract
Magnetoresistance, the change in resistance with applied magnetic fields, is crucial to the magnetic sensor technology. Linear magnetoresistance has been intensively studied in semimetals and semiconductors. However, the air-stable oxides with a large linear magnetoresistance are highly desirable but remain to be fully explored. In this paper, we report the direct observation of linear magnetoresistance in polycrystalline MoO2 without any sign of saturation up to 7 T under 50 K. Interestingly, the linear magnetoresistance reaches as large as 1500% under 7 T at 2 K. The linear field dependence is in great contrast to the parabolic behavior observed in single-crystal MoO2, probably due to phonon scattering near the grain boundaries. Our results pave the way to comprehending magneto-transport behavior in oxides and their potential applications in magnetic sensors.
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Affiliation(s)
- Yulong Su
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China; (Z.H.); (R.J.); (J.Z.)
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10
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Firouzeh S, Hossain MA, Cuerva JM, Álvarez de Cienfuegos L, Pramanik S. Chirality-Induced Spin Selectivity in Composite Materials: A Device Perspective. Acc Chem Res 2024; 57:1478-1487. [PMID: 38687873 PMCID: PMC11112739 DOI: 10.1021/acs.accounts.4c00077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/18/2024] [Accepted: 04/22/2024] [Indexed: 05/02/2024]
Abstract
ConspectusMagnetism is an area of immense fundamental and technological importance. At the atomic level, magnetism originates from electron "spin". The field of nanospintronics (or nanoscale spin-based electronics) aims to control spins in nanoscale systems, which has resulted in astronomical improvement in data storage and magnetic field sensing technologies over the past few decades, recognized by the 2007 Nobel Prize in Physics. Spins in nanoscale solid-state devices can also act as quantum bits or qubits for emerging quantum technologies, such as quantum computing and quantum sensing.Due to the fundamental connection between magnetism and spins, ferromagnets play a key role in many solid-state spintronic devices. This is because at the Fermi level, electron density of states is spin-polarized, which permits ferromagnets to act as electrical injectors and detectors of spins. Ferromagnets, however, have limitations in terms of low spin polarization at the Fermi level, stray magnetic fields, crosstalk, and thermal instability at the nanoscale. Therefore, new physics and new materials are needed to propel spintronic and quantum device technologies to the true atomic limit. Emerging new phenomena such as chirality induced spin selectivity or CISS, in which an intriguing correlation between carrier spin and medium chirality is observed, could therefore be instrumental in nanospintronics. This effect could allow molecular-scale, chirality controlled spin injection and detection without the need for any ferromagnet, thus opening a fundamentally new direction for device spintronics.While CISS finds a myriad of applications in diverse areas such as chiral separation, recognition, detection, and asymmetric catalysis, in this focused Account, we exclusively review spintronic device results of this effect due to its immense potential for future spintronics. The first generation of CISS-based spintronic devices have primarily used chiral bioorganic molecules; however, many practical limitations of these materials have also been identified. Therefore, our discussion revolves around the family of chiral composite materials, which may emerge as an ideal platform for CISS due to their ability to assimilate various desirable material properties on a single platform. This class of materials has been extensively studied by the organic chemistry community in the past decades, and we discuss the various chirality transfer mechanisms that have been identified, which play a central role in CISS. Next, we discuss CISS device studies performed on some of these chiral composite materials. Emphasis is given to the family of chiral organic-carbon allotrope composites, which have been extensively studied by the authors of this Account over the past several years. Interestingly, due to the presence of multiple materials, CISS signals from hybrid chiral systems sometimes differ from those observed in purely chiral systems. Given the sheer diversity of chiral composite materials, CISS device studies so far have been limited to only a few varieties, and this Account is expected to draw increased attention to the family of chiral composites and motivate further studies of their CISS applications.
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Affiliation(s)
- Seyedamin Firouzeh
- Department
of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Md Anik Hossain
- Department
of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Juan Manuel Cuerva
- Universidad
de Granada, Departamento de Química Orgánica, Unidad de Excelencia Química Aplicada a Biomedicina
y Medioambiente, C. U.
Fuentenueva, Avda. Severo Ochoa s/n, E-18071 Granada, Spain
| | - Luis Álvarez de Cienfuegos
- Universidad
de Granada, Departamento de Química Orgánica, Unidad de Excelencia Química Aplicada a Biomedicina
y Medioambiente, C. U.
Fuentenueva, Avda. Severo Ochoa s/n, E-18071 Granada, Spain
- Instituto
de Investigación Biosanitaria ibs., Avda. De Madrid, 15, E-18016 Granada, Spain
| | - Sandipan Pramanik
- Department
of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
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11
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Wu Q, Wang J, Zhi T, Zhuang Y, Tao Z, Shao P, Cai Q, Yang G, Xue J, Chen D, Zhang R. Boosting the Curie temperature of GaN monolayer through van der Waals heterostructures. NANOTECHNOLOGY 2024; 35:305204. [PMID: 38604152 DOI: 10.1088/1361-6528/ad3d64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 04/09/2024] [Indexed: 04/13/2024]
Abstract
The pursuit of van der Waals (vdW) heterostructures with high Curie temperature and strong perpendicular magnetic anisotropy (PMA) is vital to the advancement of next generation spintronic devices. First-principles calculations are used to study the electronic structures and magnetic characteristics of GaN/VS2vdW heterostructure under biaxial strain and electrostatic doping. Our findings show that a ferromagnetic ground state with a remarkable Curie temperature (477 K), much above room temperature, exists in GaN/VS2vdW heterostructure and 100% spin polarization efficiency. Additionally, GaN/VS2vdW heterostructure still maintains PMA under biaxial strain, which is indispensable for high-density information storage. We further explore the electron, magnetic, and transport properties of VS2/GaN/VS2vdW sandwich heterostructure, where the magnetoresistivity can reach as high as 40%. Our research indicates that the heterostructure constructed by combining the ferromagnet VS2and the non-magnetic semiconductor GaN is a promising material for vdW spin valve devices at room temperature.
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Affiliation(s)
- Qianqian Wu
- College of Electronic and Optical Engineering & College of Flexible electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, People's Republic of China
| | - Jin Wang
- College of Electronic and Optical Engineering & College of Flexible electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, People's Republic of China
| | - Ting Zhi
- College of Electronic and Optical Engineering & College of Flexible electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, People's Republic of China
| | - Yanling Zhuang
- College of Electronic and Optical Engineering & College of Flexible electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, People's Republic of China
| | - Zhikuo Tao
- College of Electronic and Optical Engineering & College of Flexible electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, People's Republic of China
| | - Pengfei Shao
- Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, People's Republic of China
| | - Qing Cai
- Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, People's Republic of China
| | - Guofeng Yang
- School of Science, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Junjun Xue
- College of Electronic and Optical Engineering & College of Flexible electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, People's Republic of China
| | - Dunjun Chen
- Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, People's Republic of China
| | - Rong Zhang
- Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, People's Republic of China
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12
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Guo L, Hu S, Gu X, Zhang R, Wang K, Yan W, Sun X. Emerging Spintronic Materials and Functionalities. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2301854. [PMID: 37309258 DOI: 10.1002/adma.202301854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/01/2023] [Indexed: 06/14/2023]
Abstract
The explosive growth of the information era has put forward urgent requirements for ultrahigh-speed and extremely efficient computations. In direct contrary to charge-based computations, spintronics aims to use spins as information carriers for data storage, transmission, and decoding, to help fully realize electronic device miniaturization and high integration for next-generation computing technologies. Currently, many novel spintronic materials have been developed with unique properties and multifunctionalities, including organic semiconductors (OSCs), organic-inorganic hybrid perovskites (OIHPs), and 2D materials (2DMs). These materials are useful to fulfill the demand for developing diverse and advanced spintronic devices. Herein, these promising materials are systematically reviewed for advanced spintronic applications. Due to the distinct chemical and physical structures of OSCs, OIHPs, and 2DMs, their spintronic properties (spin transport and spin manipulation) are discussed separately. In addition, some multifunctionalities due to photoelectric and chiral-induced spin selectivity (CISS) are overviewed, including the spin-filter effect, spin-photovoltaics, spin-light emitting devices, and spin-transistor functions. Subsequently, challenges and future perspectives of using these multifunctional materials for the development of advanced spintronics are presented.
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Affiliation(s)
- Lidan Guo
- Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Shunhua Hu
- Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Xianrong Gu
- Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Rui Zhang
- Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Kai Wang
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Physical Science and Engineering, Institute of Optoelectronics Technology, Beijing Jiaotong University, Beijing, 100044, P. R. China
| | - Wenjing Yan
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG9 2RD, UK
| | - Xiangnan Sun
- Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
- School of Material Science and Engineering, Zhengzhou University, Zhengzhou, 450001, P. R. China
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13
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Maicke A, Arzate J, Liu S, Kwon J, Smith JD, Aimone JB, Misra S, Schuman C, Cardwell SG, Incorvia JAC. Magnetic tunnel junction random number generators applied to dynamically tuned probability trees driven by spin orbit torque. NANOTECHNOLOGY 2024; 35:275204. [PMID: 38579686 DOI: 10.1088/1361-6528/ad3b01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 04/05/2024] [Indexed: 04/07/2024]
Abstract
Perpendicular magnetic tunnel junction (pMTJ)-based true-random number generators (RNGs) can consume orders of magnitude less energy per bit than CMOS pseudo-RNGs. Here, we numerically investigate with a macrospin Landau-Lifshitz-Gilbert equation solver the use of pMTJs driven by spin-orbit torque to directly sample numbers from arbitrary probability distributions with the help of a tunable probability tree. The tree operates by dynamically biasing sequences of pMTJ relaxation events, called 'coinflips', via an additional applied spin-transfer-torque current. Specifically, using a single, ideal pMTJ device we successfully draw integer samples on the interval [0, 255] from an exponential distribution based onp-value distribution analysis. In order to investigate device-to-device variations, the thermal stability of the pMTJs are varied based on manufactured device data. It is found that while repeatedly using a varied device inhibits ability to recover the probability distribution, the device variations average out when considering the entire set of devices as a 'bucket' to agnostically draw random numbers from. Further, it is noted that the device variations most significantly impact the highest level of the probability tree, with diminishing errors at lower levels. The devices are then used to draw both uniformly and exponentially distributed numbers for the Monte Carlo computation of a problem from particle transport, showing excellent data fit with the analytical solution. Finally, the devices are benchmarked against CMOS and memristor RNGs, showing faster bit generation and significantly lower energy use.
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Affiliation(s)
- Andrew Maicke
- University of Texas at Austin, Austin, TX, United States of America
| | - Jared Arzate
- University of Texas at Austin, Austin, TX, United States of America
| | - Samuel Liu
- University of Texas at Austin, Austin, TX, United States of America
| | - Jaesuk Kwon
- University of Texas at Austin, Austin, TX, United States of America
| | - J Darby Smith
- Sandia National Laboratories, Albuquerque, NM, United States of America
| | - James B Aimone
- Sandia National Laboratories, Albuquerque, NM, United States of America
| | - Shashank Misra
- Sandia National Laboratories, Albuquerque, NM, United States of America
| | - Catherine Schuman
- University of Tennessee, Knoxville, Knoxville, TN, United States of America
| | - Suma G Cardwell
- Sandia National Laboratories, Albuquerque, NM, United States of America
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14
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Zhang Y, Sun W, Cao K, Yang XX, Yang Y, Lu S, Du A, Hu C, Feng C, Wang Y, Cai J, Cui B, Piao HG, Zhao W, Zhao Y. Electric-field control of nonvolatile resistance state of perpendicular magnetic tunnel junction via magnetoelectric coupling. SCIENCE ADVANCES 2024; 10:eadl4633. [PMID: 38640249 PMCID: PMC11029801 DOI: 10.1126/sciadv.adl4633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 03/15/2024] [Indexed: 04/21/2024]
Abstract
Magnetic tunnel junctions (MTJs) are the core elements of spintronic devices. Now, the mainstream writing operation of MTJs mainly relies on electric current with high energy dissipation, which can be greatly reduced if an electric field is used instead. In this regard, strain-mediated multiferroic heterostructure composed of MTJ and ferroelectrics are promising with the advantages of room temperature and magnetic field-free as already demonstrated by MTJ with in-plane magnetic anisotropy. However, there is no such report on the perpendicular MTJs (p-MTJs), which have been commercialized. Here, we investigate electric-field control of resistance state of MgO-based p-MTJs in multiferroic heterostructures. A remarkable and nonvolatile manipulation of resistance is demonstrated at room temperature without magnetic field assistance. Through various characterizations and micromagnetic simulation, the manipulation mechanism is uncovered. Our work provides an effective avenue for manipulating p-MTJ resistance by electric fields and is notable for high density and ultralow power spintronic devices.
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Affiliation(s)
- Yike Zhang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Weideng Sun
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Kaihua Cao
- Fert Beijing Institute, School of Integrated Science and Engineering, Beihang University, Beijing 100191, China
| | - Xiao-Xue Yang
- Department of Physics, Yanbian University, Yanji 133002, China
| | - Yongqiang Yang
- Faculty of Physics and Electronic Science, Hubei University, Wuhan 430062, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Shiyang Lu
- Fert Beijing Institute, School of Integrated Science and Engineering, Beihang University, Beijing 100191, China
| | - Ao Du
- Fert Beijing Institute, School of Integrated Science and Engineering, Beihang University, Beijing 100191, China
| | - Chaoqun Hu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ce Feng
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Yutong Wang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baoshan Cui
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Hong-Guang Piao
- Department of Physics, Yanbian University, Yanji 133002, China
| | - Weisheng Zhao
- Fert Beijing Institute, School of Integrated Science and Engineering, Beihang University, Beijing 100191, China
| | - Yonggang Zhao
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
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15
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Rehman NU, Ullah A, Mahmood MA, Rahman N, Sohail M, Iqbal S, Juraev N, Althubeiti K, Al Otaibi S, Khan R. Cobalt-doped zinc oxide based memristors with nociceptor characteristics for bio-inspired technology. RSC Adv 2024; 14:11797-11810. [PMID: 38617576 PMCID: PMC11009837 DOI: 10.1039/d4ra01250j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 04/01/2024] [Indexed: 04/16/2024] Open
Abstract
Neuromorphic computing is a new field of information technology, which is inspired by the biomimetic properties of the memristor as an electronic synapse and neuron. If there are electronic receptors that can transmit exterior impulses to the internal nervous system, then the use of memristors can be expanded to artificial nerves. In this study, a layer type memristor is used to build an artificial nociceptor in a very feasible and straightforward manner. An artificial nociceptor is demonstrated here through the fabrication and characterization of a cobalt-doped zinc oxide (CZO)/Au based memristor. In order to increase threshold switching performance, the surface effects of the CZO layer are eliminated by adding cobalt cobalt-doped zinc oxide (CZO) layer between the P++-Si and Au electrodes. Allodynia, hyperalgesia, threshold, and relaxation are the four distinct nociceptive behaviours that the device displays based on the strength, rate of relapse, and duration of the external stimuli. The electrons that are trapped in or released from the CZO layer's traps are responsible for these nociceptive behaviours. A multipurpose nociceptor performance is produced by this type of CZO-based device, which is crucial for artificial intelligence system applications such as neural integrated devices with nanometer-sized characteristics.
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Affiliation(s)
- Naveed Ur Rehman
- Department of Physics, University of Lakki Marwat Lakki Marwat 2842 KP Pakistan
| | - Aziz Ullah
- Department of Physics, University of Lakki Marwat Lakki Marwat 2842 KP Pakistan
| | | | - Nasir Rahman
- Department of Physics, University of Lakki Marwat Lakki Marwat 2842 KP Pakistan
| | - Mohammad Sohail
- Department of Physics, University of Lakki Marwat Lakki Marwat 2842 KP Pakistan
| | - Shahid Iqbal
- Department of Physics, University of Wisconsin La Crosse WI 54601 USA
| | - Nizomiddin Juraev
- Faculty of Chemical Engineering, New Uzbekistan University Tashkent Uzbekistan
- Scientific and Innovation Department, Tashkent State Pedagogical University Tashkent Uzbekistan
| | - Khaled Althubeiti
- Department of Chemistry, College of Science, Taif University P.O. BOX. 110 21944 Taif Saudi Arabia
| | - Sattam Al Otaibi
- Department of Electrical Engineering, College of Engineering Taif University P.O. Box 11099 Taif 21944 Saudi Arabia
| | - Rajwali Khan
- Department of Physics, University of Lakki Marwat Lakki Marwat 2842 KP Pakistan
- Department of Physics, United Arab Emirates University Al Ain 15551 Abu Dhabi UAE
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16
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Sun W, Zhang Y, Cao K, Lu S, Du A, Huang H, Zhang S, Hu C, Feng C, Liang W, Liu Q, Mi S, Cai J, Lu Y, Zhao W, Zhao Y. Electric field control of perpendicular magnetic tunnel junctions with easy-cone magnetic anisotropic free layers. SCIENCE ADVANCES 2024; 10:eadj8379. [PMID: 38579008 PMCID: PMC10997210 DOI: 10.1126/sciadv.adj8379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 03/05/2024] [Indexed: 04/07/2024]
Abstract
Magnetic tunnel junctions (MTJs) are the core element of spintronic devices. Currently, the mainstream writing operation of MTJs is based on electric current with high energy dissipation, and it can be notably reduced if an electric field is used instead. In this regard, it is promising for electric field control of MTJ in the multiferroic heterostructure composed of MTJ and ferroelectrics via strain-mediated magnetoelectric coupling. However, there are only reports on MTJs with in-plane anisotropy so far. Here, we investigate electric field control of the resistance state of MgO-based perpendicular MTJs with easy-cone anisotropic free layers through strain-mediated magnetoelectric coupling in multiferroic heterostructures. A remarkable, nonvolatile, and reversible modulation of resistance at room temperature is demonstrated. Through local reciprocal space mapping under different electric fields for Pb(Mg1/3Nb2/3)0.7Ti0.3O3 beneath the MTJ pillar, the modulation mechanism is deduced. Our work represents a crucial step toward electric field control of spintronic devices with non-in-plane magnetic anisotropy.
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Affiliation(s)
- Weideng Sun
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Yike Zhang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Kaihua Cao
- Fert Beijing Institute, School of Integrated Science and Engineering, Beihang University, Beijing 100191, China
| | - Shiyang Lu
- Fert Beijing Institute, School of Integrated Science and Engineering, Beihang University, Beijing 100191, China
| | - Ao Du
- Fert Beijing Institute, School of Integrated Science and Engineering, Beihang University, Beijing 100191, China
| | - Haoliang Huang
- Anhui Laboratory of Advanced Photon Science and Technology and Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Sen Zhang
- College of Science, National University of Defense Technology, Changsha 410073, China
| | - Chaoqun Hu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ce Feng
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Wenhui Liang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Quan Liu
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Shu Mi
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Jianwang Cai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yalin Lu
- Anhui Laboratory of Advanced Photon Science and Technology and Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Weisheng Zhao
- Fert Beijing Institute, School of Integrated Science and Engineering, Beihang University, Beijing 100191, China
| | - Yonggang Zhao
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
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17
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Chen H, Liu L, Zhou X, Meng Z, Wang X, Duan Z, Zhao G, Yan H, Qin P, Liu Z. Emerging Antiferromagnets for Spintronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2310379. [PMID: 38183310 DOI: 10.1002/adma.202310379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 12/18/2023] [Indexed: 01/08/2024]
Abstract
Antiferromagnets constitute promising contender materials for next-generation spintronic devices with superior stability, scalability, and dynamics. Nevertheless, the perception of well-established ferromagnetic spintronics underpinned by spontaneous magnetization seemed to indicate the inadequacy of antiferromagnets for spintronics-their compensated magnetization has been perceived to result in uncontrollable antiferromagnetic order and subtle magnetoelectronic responses. However, remarkable advancements have been achieved in antiferromagnetic spintronics in recent years, with consecutive unanticipated discoveries substantiating the feasibility of antiferromagnet-centered spintronic devices. It is emphasized that, distinct from ferromagnets, the richness in complex antiferromagnetic crystal structures is the unique and essential virtue of antiferromagnets that can open up their endless possibilities of novel phenomena and functionality for spintronics. In this Perspective, the recent progress in antiferromagnetic spintronics is reviewed, with a particular focus on that based on several kinds of antiferromagnets with special antiferromagnetic crystal structures. The latest developments in efficiently manipulating antiferromagnetic order, exploring novel antiferromagnetic physical responses, and demonstrating prototype antiferromagnetic spintronic devices are discussed. An outlook on future research directions is also provided. It is hoped that this Perspective can serve as guidance for readers who are interested in this field and encourage unprecedented studies on antiferromagnetic spintronic materials, phenomena, and devices.
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Affiliation(s)
- Hongyu Chen
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Li Liu
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Xiaorong Zhou
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Ziang Meng
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Xiaoning Wang
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Zhiyuan Duan
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Guojian Zhao
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Han Yan
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Peixin Qin
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Zhiqi Liu
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
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18
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Fang N, Wu C, Zhang Y, Li Z, Zhou Z. Perspectives: Light Control of Magnetism and Device Development. ACS NANO 2024; 18:8600-8625. [PMID: 38469753 DOI: 10.1021/acsnano.3c13002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Accurately controlling magnetic and spin states presents a significant challenge in spintronics, especially as demands for higher data storage density and increased processing speeds grow. Approaches such as light control are gradually supplanting traditional magnetic field methods. Traditionally, the modulation of magnetism was predominantly achieved through polarized light with the help of ultrafast light technologies. With the growing demand for energy efficiency and multifunctionality in spintronic devices, integrating photovoltaic materials into magnetoelectric systems has introduced more physical effects. This development suggests that sunlight will play an increasingly pivotal role in manipulating spin orientation in the future. This review introduces and concludes the influence of various light types on magnetism, exploring mechanisms such as magneto-optical (MO) effects, light-induced magnetic phase transitions, and spin photovoltaic effects. This review briefly summarizes recent advancements in the light control of magnetism, especially sunlight, and their potential applications, providing an optimistic perspective on future research directions in this area.
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Affiliation(s)
- Ning Fang
- School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China
| | - Changqing Wu
- School of Environmental Science and Engineering, Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China
| | - Yuzhe Zhang
- School of Environmental Science and Engineering, Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China
| | - Zhongyu Li
- School of Environmental Science and Engineering, Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China
| | - Ziyao Zhou
- School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China
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19
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Harfah H, Wicaksono Y, Sunnardianto GK, Majidi MA, Kusakabe K. Ultra-thin van der Waals magnetic tunnel junction based on monoatomic boron vacancy of hexagonal boron nitride. Phys Chem Chem Phys 2024; 26:9733-9740. [PMID: 38470432 DOI: 10.1039/d4cp00218k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
We present a novel strategy to create a van der Waals-based magnetic tunnel junction (MTJ) comprising a three-atom layer of graphene (Gr) sandwiched with hexagonal boron nitride (hBN) layers by introducing a monoatomic boron vacancy in each hBN layer. The magnetic properties and electronic structure of the system were investigated using density functional theory (DFT) and the transmission probability of the MTJ was investigated using the Landauer-Büttiker formalism within the non-equilibrium Green function method. The Stoner gap was created between the spin-majority channel and the spin-minority channel on the local density of states of the hBN monoatomic boron-vacancy (VB) near the Fermi energy, creating a possible control of the spin valve by considering two magnetic alignment of hBN(VB) layers, anti-parallel configuration (APC) and parallel configuration (PC). The transmission probability calculation results showed a high electron transmission in the PC of the hBN(VB) layers and a low transmission when the APC was considered. A high tunneling magnetoresistance (TMR) ratio of approximately 400% was observed when comparing the APC and PC of the hBN(VB) layers in hBN(VB)/Gr/hBN(VB), giving the highest TMR ratio for the thinnest MTJ system.
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Affiliation(s)
- Halimah Harfah
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-Cho, Toyonaka, Osaka 560-0043, Japan.
| | - Yusuf Wicaksono
- RIKEN Cluster for Pioneering Research (CPR), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Gagus Ketut Sunnardianto
- Research Center for Quantum Physics, National Research and Innovation Agency (BRIN), Tangerang Selatan, Banten, 15314, Indonesia
- Research Collaboration Center for Quantum Technology 2.0, Bandung 40132, Indonesia
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Muhammad Aziz Majidi
- Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Kampus UI Depok, Depok 16424, Indonesia
| | - Koichi Kusakabe
- School of Science, Graduate School of Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, 678-1297, Hyogo, Japan
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20
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Varignon J. Unexpected Competition between Ferroelectricity and Rashba Effects in Epitaxially Strained SrTiO_{3}. PHYSICAL REVIEW LETTERS 2024; 132:106401. [PMID: 38518324 DOI: 10.1103/physrevlett.132.106401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 01/30/2024] [Indexed: 03/24/2024]
Abstract
The Rashba parameter α_{R} is usually assumed to scale linearly with the amplitude of polar displacements by construction of the spin-orbit interaction. On the basis of first-principles simulations, ferroelectric phases of SrTiO_{3} reached under epitaxial compressive strain are characterized by (i) large Rashba effects at the bottom of the conduction band near the paraelectric-ferroelectric boundary and (ii) an unexpected suppression of the phenomena when the amplitude of polar displacements increases. This peculiar behavior is ascribed to the inverse dependence of the Rashba parameter with the crystal field Δ_{CF} induced by the polar displacements that alleviates the degeneracy of Ti t_{2g} states and annihilates the Rashba effects. Although α_{R} has intrinsically a linear dependance on polar displacements, the latter becomes antagonist to Rashba phenomena at large polar mode amplitude. Thus, the Rashba coefficient may be bound to an upper value.
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Affiliation(s)
- Julien Varignon
- CRISMAT, ENSICAEN, Normandie Université, UNICAEN, CNRS, 14000 Caen, France
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21
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Ai W, Chen F, Liu Z, Yuan X, Zhang L, He Y, Dong X, Fu H, Luo F, Deng M, Wang R, Wu J. Observation of giant room-temperature anisotropic magnetoresistance in the topological insulator β-Ag 2Te. Nat Commun 2024; 15:1259. [PMID: 38341422 DOI: 10.1038/s41467-024-45643-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
Achieving room-temperature high anisotropic magnetoresistance ratios is highly desirable for magnetic sensors with scaled supply voltages and high sensitivities. However, the ratios in heterojunction-free thin films are currently limited to only a few percent at room temperature. Here, we observe a high anisotropic magnetoresistance ratio of -39% and a giant planar Hall effect (520 μΩ⋅cm) at room temperature under 9 T in β-Ag2Te crystals grown by chemical vapor deposition. We propose a theoretical model of anisotropic scattering - induced by a Dirac cone tilt and modulated by intrinsic properties of effective mass and sound velocity - as a possible origin. Moreover, small-size angle sensors with a Wheatstone bridge configuration were fabricated using the synthesized β-Ag2Te crystals. The sensors exhibited high output response (240 mV/V), high angle sensitivity (4.2 mV/V/°) and small angle error (<1°). Our work translates the developments in topological insulators to a broader impact on practical applications such as high-field magnetic and angle sensors.
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Affiliation(s)
- Wei Ai
- Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensor Interdisciplinary Science Center, School of Materials Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Fuyang Chen
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics, South China Normal University, Guangzhou, 510006, China
| | - Zhaochao Liu
- Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensor Interdisciplinary Science Center, School of Materials Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Xixi Yuan
- Center of Quantum Materials and Devices & College of Physics, Chongqing University, Chongqing, 401331, China
| | - Lei Zhang
- Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensor Interdisciplinary Science Center, School of Materials Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Yuyu He
- Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensor Interdisciplinary Science Center, School of Materials Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Xinyue Dong
- Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensor Interdisciplinary Science Center, School of Materials Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Huixia Fu
- Center of Quantum Materials and Devices & College of Physics, Chongqing University, Chongqing, 401331, China.
| | - Feng Luo
- Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensor Interdisciplinary Science Center, School of Materials Science and Engineering, Nankai University, Tianjin, 300350, China.
| | - Mingxun Deng
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics, South China Normal University, Guangzhou, 510006, China.
| | - Ruiqiang Wang
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics, South China Normal University, Guangzhou, 510006, China
| | - Jinxiong Wu
- Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensor Interdisciplinary Science Center, School of Materials Science and Engineering, Nankai University, Tianjin, 300350, China.
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22
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Fedchenko O, Minár J, Akashdeep A, D’Souza SW, Vasilyev D, Tkach O, Odenbreit L, Nguyen Q, Kutnyakhov D, Wind N, Wenthaus L, Scholz M, Rossnagel K, Hoesch M, Aeschlimann M, Stadtmüller B, Kläui M, Schönhense G, Jungwirth T, Hellenes AB, Jakob G, Šmejkal L, Sinova J, Elmers HJ. Observation of time-reversal symmetry breaking in the band structure of altermagnetic RuO 2. SCIENCE ADVANCES 2024; 10:eadj4883. [PMID: 38295181 PMCID: PMC10830110 DOI: 10.1126/sciadv.adj4883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 12/29/2023] [Indexed: 02/02/2024]
Abstract
Altermagnets are an emerging elementary class of collinear magnets. Unlike ferromagnets, their distinct crystal symmetries inhibit magnetization while, unlike antiferromagnets, they promote strong spin polarization in the band structure. The corresponding unconventional mechanism of time-reversal symmetry breaking without magnetization in the electronic spectra has been regarded as a primary signature of altermagnetism but has not been experimentally visualized to date. We directly observe strong time-reversal symmetry breaking in the band structure of altermagnetic RuO2 by detecting magnetic circular dichroism in angle-resolved photoemission spectra. Our experimental results, supported by ab initio calculations, establish the microscopic electronic structure basis for a family of interesting phenomena and functionalities in fields ranging from topological matter to spintronics, which are based on the unconventional time-reversal symmetry breaking in altermagnets.
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Affiliation(s)
- Olena Fedchenko
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
| | - Jan Minár
- University of West Bohemia, New Technologies Research Center, Plzen 30100, Czech Republic
| | - Akashdeep Akashdeep
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
| | - Sunil Wilfred D’Souza
- University of West Bohemia, New Technologies Research Center, Plzen 30100, Czech Republic
| | - Dmitry Vasilyev
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
| | - Olena Tkach
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
- Sumy State University, Rymski-Korsakov 2, 40007 Sumy, Ukraine
| | - Lukas Odenbreit
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
| | - Quynh Nguyen
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | | | - Nils Wind
- Ruprecht Haensel Laboratory, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
- Institut für Experimentalphysik, Universität Hamburg, 22761 Hamburg, Germany
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - Lukas Wenthaus
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Markus Scholz
- Ruprecht Haensel Laboratory, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Kai Rossnagel
- Ruprecht Haensel Laboratory, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - Moritz Hoesch
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Martin Aeschlimann
- Universität Kaiserslautern, Department of Physics, 67663 Kaiserslautern, Germany
| | - Benjamin Stadtmüller
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
| | - Mathias Kläui
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
| | - Gerd Schönhense
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
| | - Tomas Jungwirth
- Institute of Physics Academy of Sciences of the Czech Republic, Cukrovarnick’a 10, Praha 6, Czech Republic
- School of Physics and Astronomy, University of Nottingham, NG7 2RD Nottingham, UK
| | - Anna Birk Hellenes
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
| | - Gerhard Jakob
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
| | - Libor Šmejkal
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
- Institute of Physics Academy of Sciences of the Czech Republic, Cukrovarnick’a 10, Praha 6, Czech Republic
| | - Jairo Sinova
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
- Institute of Physics Academy of Sciences of the Czech Republic, Cukrovarnick’a 10, Praha 6, Czech Republic
| | - Hans-Joachim Elmers
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55128 Mainz, Germany
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23
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Krempaský J, Šmejkal L, D'Souza SW, Hajlaoui M, Springholz G, Uhlířová K, Alarab F, Constantinou PC, Strocov V, Usanov D, Pudelko WR, González-Hernández R, Birk Hellenes A, Jansa Z, Reichlová H, Šobáň Z, Gonzalez Betancourt RD, Wadley P, Sinova J, Kriegner D, Minár J, Dil JH, Jungwirth T. Altermagnetic lifting of Kramers spin degeneracy. Nature 2024; 626:517-522. [PMID: 38356066 PMCID: PMC10866710 DOI: 10.1038/s41586-023-06907-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 11/28/2023] [Indexed: 02/16/2024]
Abstract
Lifted Kramers spin degeneracy (LKSD) has been among the central topics of condensed-matter physics since the dawn of the band theory of solids1,2. It underpins established practical applications as well as current frontier research, ranging from magnetic-memory technology3-7 to topological quantum matter8-14. Traditionally, LKSD has been considered to originate from two possible internal symmetry-breaking mechanisms. The first refers to time-reversal symmetry breaking by magnetization of ferromagnets and tends to be strong because of the non-relativistic exchange origin15. The second applies to crystals with broken inversion symmetry and tends to be comparatively weaker, as it originates from the relativistic spin-orbit coupling (SOC)16-19. A recent theory work based on spin-symmetry classification has identified an unconventional magnetic phase, dubbed altermagnetic20,21, that allows for LKSD without net magnetization and inversion-symmetry breaking. Here we provide the confirmation using photoemission spectroscopy and ab initio calculations. We identify two distinct unconventional mechanisms of LKSD generated by the altermagnetic phase of centrosymmetric MnTe with vanishing net magnetization20-23. Our observation of the altermagnetic LKSD can have broad consequences in magnetism. It motivates exploration and exploitation of the unconventional nature of this magnetic phase in an extended family of materials, ranging from insulators and semiconductors to metals and superconductors20,21, that have been either identified recently or perceived for many decades as conventional antiferromagnets21,24,25.
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Affiliation(s)
- J Krempaský
- Photon Science Division, Paul Scherrer Institut, Villigen, Switzerland.
| | - L Šmejkal
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz, Germany
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic
| | - S W D'Souza
- New Technologies Research Center, University of West Bohemia, Plzeň, Czech Republic
| | - M Hajlaoui
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University of Linz, Linz, Austria
| | - G Springholz
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University of Linz, Linz, Austria
| | - K Uhlířová
- Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - F Alarab
- Photon Science Division, Paul Scherrer Institut, Villigen, Switzerland
| | - P C Constantinou
- Photon Science Division, Paul Scherrer Institut, Villigen, Switzerland
| | - V Strocov
- Photon Science Division, Paul Scherrer Institut, Villigen, Switzerland
| | - D Usanov
- Photon Science Division, Paul Scherrer Institut, Villigen, Switzerland
| | - W R Pudelko
- Photon Science Division, Paul Scherrer Institut, Villigen, Switzerland
- Physik-Institut, Universität Zürich, Zürich, Switzerland
| | - R González-Hernández
- Grupo de Investigación en Física Aplicada, Departamento de Física, Universidad del Norte, Barranquilla, Colombia
| | - A Birk Hellenes
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz, Germany
| | - Z Jansa
- New Technologies Research Center, University of West Bohemia, Plzeň, Czech Republic
| | - H Reichlová
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic
| | - Z Šobáň
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic
| | | | - P Wadley
- School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
| | - J Sinova
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz, Germany
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic
| | - D Kriegner
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic
| | - J Minár
- New Technologies Research Center, University of West Bohemia, Plzeň, Czech Republic.
| | - J H Dil
- Photon Science Division, Paul Scherrer Institut, Villigen, Switzerland
- Institut de Physique, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - T Jungwirth
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic.
- School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom.
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24
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Tiwari RK, Nabi R, Kumawat RL, Pathak B, Rajaraman G. Enhancing Spin-Transport Characteristics, Spin-Filtering Efficiency, and Negative Differential Resistance in Exchange-Coupled Dinuclear Co(II) Complexes for Molecular Spintronics Applications. Inorg Chem 2024; 63:316-328. [PMID: 38114426 DOI: 10.1021/acs.inorgchem.3c03200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Single-molecule spintronics, where electron transport occurs via a paramagnetic molecule, has gained wide attention due to its potential applications in the area of memory devices to switches. While numerous organic and some inorganic complexes have been employed over the years, there are only a few attempts to employ exchange coupled dinuclear complexes at the interface, and the advantage of fabricating such a molecular spintronics device in the observation of switchable Kondo resonance was demonstrated recently in the dinuclear [Co2(L)(hfac)4] (1) complex (Wagner et al., Nat. Nanotechnol. 2013, 8, 575-579). In this work, employing an array of theoretical tools such as density functional theory (DFT), the ab initio CASSCF/NEVPT2 method, and DFT combined with nonequilibrium Green Function (NEGF) formalism, we studied in detail the role of magnetic coupling, ligand field, and magnetic anisotropy in the transport characteristics of complex 1. Particularly, our calculations not only reproduce the current-voltage (I-V) characteristics observed in experiments but also unequivocally establish that these arise from an exchange-coupled singlet state that arises due to antiferromagnetic coupling between two high-spin Co(II) centers. Further, the estimated spin Hamiltonian parameters such as J, g values, and D and E/D values are only marginally altered for the molecule at the interface. Further, the exchange-coupled state was found to have very similar transport responses, despite possessing significantly different geometries. Our transport calculations unveil a new feature of the negative differential resistance (NDR) effect on 1 at the bias voltage of 0.9 V, which agrees with the experimental I-V characteristics reported. The spin-filtering efficiency (SFE) computed for the spin-coupled states was found to be only marginal (∼25%); however, if the ligand field is fine-tuned to obtain a low-spin Co(II) center, a substantial SFE of 44% was noted. This spin-coupled state also yields a very strong NDR with a peak-to-valley ratio (PVR) of ∼56 - a record number that has not been witnessed so far in this class of compounds. Additionally, we have established further magnetostructural-transport correlations, providing valuable insights into how microscopic spin Hamiltonian parameters can be associated with SFE. Several design clues to improve the spin-transport characteristics, SFE and NDR in this class of molecule, are offered.
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Affiliation(s)
| | - Rizwan Nabi
- Department of Chemistry, IIT Bombay, Powai, Mumbai 400076, India
| | | | - Biswarup Pathak
- Department of Chemistry, IIT Indore, Indore, Madhya Pradesh 453-552, India
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25
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Song I, You L, Chen K, Lee WJ, Mei J. Chiroptical Switching of Electrochromic Polymer Thin Films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2307057. [PMID: 37897242 DOI: 10.1002/adma.202307057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 10/17/2023] [Indexed: 10/30/2023]
Abstract
The interaction between light and chiroptical polymers plays a crucial role in chiroptics, spintronics, and chiral-spin selectivity. Despite considerable successes in creating dissymmetric polymer films, the elucidation of chiroptical activities under electrochemical switching remains unexplored. Here homogeneous chiral electrochromics is reported using chiral assembly of conjugated polymers through a transient solidification process with molecular chiral templates. In their neutral state, the chiral electrochromic polymers directly produce a remarkably dissymmetric polarization-dependent transmittance. The circular dichroism (CD) and dissymmetric transmission can be tuned by adjusting the doping level of the electrochemically active polymer films. Under high levels of oxidation, the chiroptical activities are reversed with strong bleaching in the visible, leading to formation of monosignate CD spectra over the infrared region. The matching between circular polarization handedness and chirality of chiroptical polymers makes a distinct impact on optical contrast and color switching dynamics due to the flipped chiroptical activities through polymer redox reactions. The differential circularly polarized transmission in the chiral see-through display can make a well-resolved color change in human eyes, demonstrating proof-of-concept devices for 3D imaging and information encryption. This work serves as a foundation to develop advanced on-chip fabrication of circular polarization-multiplexed display in flexible and highly integrated platforms.
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Affiliation(s)
- Inho Song
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Liyan You
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Ke Chen
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Won-June Lee
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Jianguo Mei
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA
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26
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Yu X, Zhang X, Wang J. Fully Electrically Controlled van der Waals Multiferroic Tunnel Junctions. ACS NANO 2023; 17:25348-25356. [PMID: 38078697 DOI: 10.1021/acsnano.3c08747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
The fully electrical control of the magnetic states in magnetic tunnel junctions is highly pursued for the development of the next generation of low-power and high-density information technology. However, achieving this functionality remains a formidable challenge at present. Here we propose an effective strategy by constructing a trilayer van der Waals multiferroic structure, consisting of CrI3-AgBiPSe6 and Cr2Ge2Te6-In2Se3, to achieve full-electrical control of multiferroic tunnel junctions. Within this structure, two different magnetic states of the magnetic bilayers (CrI3/Cr2Ge2Te6) can be modulated and switched in response to the polarization direction of the adjacent ferroelectric materials (AgBiPSe6/In2Se3). The intriguing magnetization reversal is mainly attributed to the polarization-field-induced band structure shift and interfacial charge transfer. On this basis, we further design two multiferroic tunnel junction devices, namely, graphene/CrI3-AgBiPSe6/graphene and graphene/Cr2Ge2Te6-In2Se3/graphene. In these devices, good interfacial Ohmic contacts are successfully obtained between the graphene electrode and the heterojunction, leading to an ultimate tunneling magnetoresistance of 9.3 × 106%. This study not only proposes a feasible strategy and identifies a promising candidate for achieving fully electrically controlled multiferroic tunnel junctions but also provides insights for designing other advanced spintronic devices.
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Affiliation(s)
- Xing Yu
- Key Laboratory of Quantum Materials and Devices of Ministry of Education School of Physics, Southeast University, Nanjing 211189, People's Republic of China
| | - Xiwen Zhang
- School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China
| | - Jinlan Wang
- Key Laboratory of Quantum Materials and Devices of Ministry of Education School of Physics, Southeast University, Nanjing 211189, People's Republic of China
- Suzhou Laboratory, Suzhou 215004, People's Republic of China
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27
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Hasan MU, Kossak AE, Beach GSD. Large exchange bias enhancement and control of ferromagnetic energy landscape by solid-state hydrogen gating. Nat Commun 2023; 14:8510. [PMID: 38129380 PMCID: PMC10740009 DOI: 10.1038/s41467-023-43955-z] [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: 10/23/2023] [Accepted: 11/24/2023] [Indexed: 12/23/2023] Open
Abstract
Voltage control of exchange bias is desirable for spintronic device applications, however dynamic modulation of the unidirectional coupling energy in ferromagnet/antiferromagnet bilayers has not yet been achieved. Here we show that by solid-state hydrogen gating, perpendicular exchange bias can be enhanced by > 100% in a reversible and analog manner, in a simple Co/Co0.8Ni0.2O heterostructure at room temperature. We show that this phenomenon is an isothermal analog to conventional field-cooling and that sizable changes in average coupling energy can result from small changes in AFM grain rotatability. Using this method, we show that a bi-directionally stable ferromagnet can be made unidirectionally stable, with gate voltage alone. This work provides a means to dynamically reprogram exchange bias, with broad applicability in spintronics and neuromorphic computing, while simultaneously illuminating fundamental aspects of exchange bias in polycrystalline films.
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Affiliation(s)
- M Usama Hasan
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka, 1000, Bangladesh
| | - Alexander E Kossak
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Geoffrey S D Beach
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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28
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Verma D, Chen TC, Liu B, Lai CS. Bi 2O 2Se-based CBRAM integrated artificial synapse. Heliyon 2023; 9:e22512. [PMID: 38107308 PMCID: PMC10724560 DOI: 10.1016/j.heliyon.2023.e22512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/30/2023] [Accepted: 11/14/2023] [Indexed: 12/19/2023] Open
Abstract
Integrating two-dimensional (2D) semiconducting materials into memristor structures has paved the way for emerging 2D materials to be employed in a vast field of memory applications. Bismuth oxyselenide (Bi2O2Se), a 2D material with high electron mobility, has attracted significant research interest owing to its great potential in various fields of advanced applications. Here, we explore the out-of-plane intrinsic switching behavior of few-layered Bi2O2Se via a cross point device for application in conductive bridge random access memory (CBRAM) and artificial synapses for neuromorphic computing. Via state-of-the-art methods, CVD-grown Bi2O2Se nanoplate is applied as a switching material (SM) in an Al/Cu/Bi2O2Se/Pd CBRAM structure. The device exhibits ∼90 consecutive DC cycles with a tight distribution of the SET/RESET voltages under a compliance current (CC) of 1 mA, a retention of over 10 ks, and multilevel switching characteristics showing four distinct states at Vread values of 0.1, 0.2, 0.25, and 0.3 V. Moreover, an artificial synapse is realized with potentiation and depression by modulating the conductance. The switching mechanism is explained via Cu migration through Bi2O2Se based on HRTEM analysis. The present structure shows potential for future integrated memory applications.
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Affiliation(s)
- Dharmendra Verma
- Department of Electronic Engineering, Chang Gung University, Taoyuan 33302, Taiwan
| | - Tsung-Cheng Chen
- Department of Electronic Engineering, Chang Gung University, Taoyuan 33302, Taiwan
| | - Bo Liu
- Faculty of Information Technology, College of Microelectronics, Beijing University of Technology, Beijing 100124, People’s Republic of China
| | - Chao-Sung Lai
- Department of Electronic Engineering, Chang Gung University, Taoyuan 33302, Taiwan
- Department of Nephrology, Chang Gung Memorial Hospital, Linkou 33302, Taiwan
- Department of Materials Engineering, Ming-Chi University of Technology, New Taipei City 24301, Taiwan
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29
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Yang Y, Hong L, Bellaiche L, Xiang H. Toward Ultimate Memory with Single-Molecule Multiferroics. J Am Chem Soc 2023; 145:25357-25364. [PMID: 37948323 DOI: 10.1021/jacs.3c09294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
The demand for high-density storage is urgent in the current era of data explosion. Recently, several single-molecule (-atom) magnets and ferroelectrics have been reported to be promising candidates for high-density storage. As another promising candidate, single-molecule multiferroics are not only small in size but also possess ferroelectric and magnetic orderings, which can sometimes be strongly coupled and used as data storage to realize the combination of electric writing and magnetic reading. However, they have been rarely proposed and have never been experimentally reported. Here, by building Hamiltonian models, we propose a new model of single-molecule multiferroics in which electric dipoles and magnetic moments are parallel and can rotate with the rotation of the single molecule. Furthermore, by performing spin-lattice dynamics simulations, we reveal the conditions (e.g., large enough single-ion anisotropy and an appropriate electric field) under which the new single-molecule multiferroic can arise. Based on this model, as well as first-principles calculations, a realistic example of Co(NH3)4N@SWCNT is constructed and numerically confirmed to demonstrate the feasibility of the new single-molecule multiferroic model. Our work not only sheds light on the discovery of single-molecule multiferroics but also provides a new guideline to design multifunctional materials for ultimate memory devices.
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Affiliation(s)
- Yali Yang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China
- Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, Shanghai 200030, China
| | - Liangliang Hong
- Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, Shanghai 200030, China
| | - Laurent Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Hongjun Xiang
- Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, Shanghai 200030, China
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30
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Cheng D, Song B, Kang JH, Sundahl C, Edgeton AL, Luo L, Park JM, Collantes YG, Hellstrom EE, Mootz M, Perakis IE, Eom CB, Wang J. Study of Elastic and Structural Properties of BaFe 2As 2 Ultrathin Film Using Picosecond Ultrasonics. MATERIALS (BASEL, SWITZERLAND) 2023; 16:7031. [PMID: 37959629 PMCID: PMC10650054 DOI: 10.3390/ma16217031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/30/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023]
Abstract
We obtain the through-thickness elastic stiffness coefficient (C33) in nominal 9 nm and 60 nm BaFe2As2 (Ba-122) thin films by using picosecond ultrasonics. Particularly, we reveal the increase in elastic stiffness as film thickness decreases from bulk value down to 9 nm, which we attribute to the increase in intrinsic strain near the film-substrate interface. Our density functional theory (DFT) calculations reproduce the observed acoustic oscillation frequencies well. In addition, temperature dependence of longitudinal acoustic (LA) phonon mode frequency for 9 nm Ba-122 thin film is reported. The frequency change is attributed to the change in Ba-122 orthorhombicity (a-b)/(a+b). This conclusion can be corroborated by our previous ultrafast ellipticity measurements in 9 nm Ba-122 thin film, which exhibit strong temperature dependence and indicate the structural phase transition temperature Ts.
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Affiliation(s)
- Di Cheng
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA; (D.C.); (B.S.); (L.L.); (J.-M.P.)
- Ames National Laboratory-USDOE, Ames, IA 50011, USA
| | - Boqun Song
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA; (D.C.); (B.S.); (L.L.); (J.-M.P.)
- Ames National Laboratory-USDOE, Ames, IA 50011, USA
| | - Jong-Hoon Kang
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA; (J.-H.K.); (C.S.); (A.L.E.); (C.-B.E.)
| | - Chris Sundahl
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA; (J.-H.K.); (C.S.); (A.L.E.); (C.-B.E.)
| | - Anthony L. Edgeton
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA; (J.-H.K.); (C.S.); (A.L.E.); (C.-B.E.)
| | - Liang Luo
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA; (D.C.); (B.S.); (L.L.); (J.-M.P.)
- Ames National Laboratory-USDOE, Ames, IA 50011, USA
| | - Joong-Mok Park
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA; (D.C.); (B.S.); (L.L.); (J.-M.P.)
- Ames National Laboratory-USDOE, Ames, IA 50011, USA
| | - Yesusa G. Collantes
- Applied Superconductivity Center, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA (E.E.H.)
| | - Eric E. Hellstrom
- Applied Superconductivity Center, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA (E.E.H.)
| | - Martin Mootz
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294-1170, USA; (M.M.); (I.E.P.)
| | - Ilias E. Perakis
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294-1170, USA; (M.M.); (I.E.P.)
| | - Chang-Beom Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA; (J.-H.K.); (C.S.); (A.L.E.); (C.-B.E.)
| | - Jigang Wang
- Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA; (D.C.); (B.S.); (L.L.); (J.-M.P.)
- Ames National Laboratory-USDOE, Ames, IA 50011, USA
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31
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Jia J, Lan Y. Synthesis, Characterization, and Applications of Nanomaterials for Energy Conversion and Storage. Molecules 2023; 28:7383. [PMID: 37959802 PMCID: PMC10647492 DOI: 10.3390/molecules28217383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
Ever since the commencement of the Industrial Revolution in Great Britain in the mid-18th century, the annual global energy consumption from various fossil fuels, encompassing wood, coal, natural gas, and petroleum, has demonstrated an exponential surge over the past four centuries [...].
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Affiliation(s)
- Jin Jia
- Key Laboratory of Spin Electron and Nanomaterials of Anhui Higher Education Institutes, Suzhou University, Suzhou 234000, China
| | - Yucheng Lan
- Department of Physics and Engineering Physics, Morgan State University, Baltimore, MD 21251, USA
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32
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Lu Y, Yuan Y, Liu R, Liu T, Chen J, Wei L, Wu D, Zhang W, You B, Du J. Improved resistive switching performance and realized electric control of exchange bias in a NiO/HfO 2 bilayer structure. Phys Chem Chem Phys 2023; 25:24436-24447. [PMID: 37655730 DOI: 10.1039/d3cp03106c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
The fluctuation of switching parameters is unavoidable in conductive filaments (CFs)-type resistive switching (RS) devices, which restricts the application in resistive random-access memory. Here, we employed an uninsulated antiferromagnetic (AFM) NiO layer adhered to a well-insulating HfO2 layer to effectively suppress the RS fluctuation by achieving forming-free, narrower set voltage distribution, a more stable on/off ratio, and better endurance in comparison with single-HfO2-layer based RS devices. The conduction scaling behavior indicates that the NiO/HfO2 bilayer has a smaller scale parameter S0 (lateral dimension of the bottleneck for the CFs). Besides this, considering some preexisting conductive paths in the NiO layer, the electric fields and the formation/rupture of CFs can be highly localized, leading to reduced switching fluctuation and improved RS performance in the NiO/HfO2-based RS devices. Moreover, asymmetric I-V curves measured in a high resistance state (HRS) in positively and negatively biased regions and the electric modulation of exchange bias (EB) arising from the Co-NiO interfacial coupling are favorable for revealing the inherent mechanism for RS. The coexistence of RS and EB is also useful to the design of novel multifunctional memory devices.
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Affiliation(s)
- Yu Lu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.
| | - Yuan Yuan
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.
| | - Ruobai Liu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.
| | - Tianyu Liu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.
| | - Jiarui Chen
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.
| | - Lujun Wei
- School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210046, P. R. China
| | - Di Wu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.
| | - Wei Zhang
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.
| | - Biao You
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.
| | - Jun Du
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, P. R. China
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33
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Meng K, Guo L, Sun X. Strategies and applications of generating spin polarization in organic semiconductors. NANOSCALE HORIZONS 2023; 8:1132-1154. [PMID: 37424331 DOI: 10.1039/d3nh00101f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The advent of spintronics has undoubtedly revolutionized data storage, processing, and sensing applications. Organic semiconductors (OSCs), characterized by long spin relaxation times (>μs) and abundant spin-dependent properties, have emerged as promising materials for advanced spintronic applications. To successfully implement spin-related functions in organic spintronic devices, the four fundamental processes of spin generation, transport, manipulation, and detection form the main building blocks and are commonly in demand. Thereinto, the effective generation of spin polarization in OSCs is a precondition, but in practice, this has not been an easy task. In this context, considerable efforts have been made on this topic, covering novel materials systems, spin-dependent theories, and device fabrication technologies. In this review, we underline recent advances in external spin injection and organic property-induced spin polarization, according to the distinction between the sources of spin polarization. We focused mainly on summarizing and discussing both the physical mechanism and representative research on spin generation in OSCs, especially for various spin injection methods, organic magnetic materials, the chiral-induced spin selectivity effect, and the spinterface effect. Finally, the challenges and prospects that allow this topic to continue to be dynamic were outlined.
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Affiliation(s)
- Ke Meng
- Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Lidan Guo
- Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
| | - Xiangnan Sun
- Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, P. R. China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
- School of Material Science and Engineering, Zhengzhou University, Zhengzhou 450001, P. R. China
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34
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Ghising P, Biswas C, Lee YH. Graphene Spin Valves for Spin Logic Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209137. [PMID: 36618004 DOI: 10.1002/adma.202209137] [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: 10/04/2022] [Revised: 11/23/2022] [Indexed: 06/09/2023]
Abstract
An alternative to charge-based electronics identifies the spin degree of freedom for information communication and processing. The long spin-diffusion length in graphene at room temperature demonstrates its ability for highly scalable spintronics. The development of the graphene spin valve (SV) has inspired spin devices in graphene including spin field-effect transistors and spin majority logic gates. A comprehensive picture of spin transport in graphene SVs is required for further development of spin logic. This review examines the advances in graphene SVs and their role in the development of spin logic devices. Different transport and scattering mechanisms in charge and spin are discussed. Furthermore, the on/off switching energy between graphene SVs and charge-based FETs is compared to highlight their prospects for low-power devices. The challenges and perspectives that need to be addressed for the future development of spin logic devices are then outlined.
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Affiliation(s)
- Pramod Ghising
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Chandan Biswas
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
- Department of Energy Science, Department of Physics, Sungkyunkwan University, Suwon, 16419, Republic of Korea
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35
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Seifu D, Peng Q, Sze K, Hou J, Gao F, Lan Y. Electromagnetic Radiation Effects on MgO-Based Magnetic Tunnel Junctions: A Review. Molecules 2023; 28:molecules28104151. [PMID: 37241892 DOI: 10.3390/molecules28104151] [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: 10/20/2022] [Revised: 05/12/2023] [Accepted: 05/13/2023] [Indexed: 05/28/2023] Open
Abstract
Magnetic tunnel junctions (MTJs) have been widely utilized in sensitive sensors, magnetic memory, and logic gates due to their tunneling magnetoresistance. Moreover, these MTJ devices have promising potential for renewable energy generation and storage. Compared with Si-based devices, MTJs are more tolerant to electromagnetic radiation. In this review, we summarize the functionalities of MgO-based MTJ devices under different electromagnetic irradiation environments, with a focus on gamma-ray radiation. We explore the effects of these radiation exposures on the MgO tunnel barriers, magnetic layers, and interfaces to understand the origin of their tolerance. This review enhances our knowledge of the radiation tolerance of MgO-based MTJs, improves the design of these MgO-based MTJ devices with better tolerances, and provides information to minimize the risks of irradiation under various irradiation environments. This review starts with an introduction to MTJs and irradiation backgrounds, followed by the fundamental properties of MTJ materials, such as the MgO barrier and magnetic layers. Then, we review and discuss the MTJ materials and devices' radiation tolerances under different irradiation environments, including high-energy cosmic radiation, gamma-ray radiation, and lower-energy electromagnetic radiation (X-ray, UV-vis, infrared, microwave, and radiofrequency electromagnetic radiation). In conclusion, we summarize the radiation effects based on the published literature, which might benefit material design and protection.
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Affiliation(s)
- Dereje Seifu
- Department of Physics and Engineering Physics, Morgan State University, Baltimore, MD 21251, USA
| | - Qing Peng
- Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
- K. A. CARE Energy Research and Innovation Center at Dhahran, Dhahran 31261, Saudi Arabia
- Hydrogen and Energy Storage Center, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - Kit Sze
- Department of Physics and Engineering Physics, Morgan State University, Baltimore, MD 21251, USA
| | - Jie Hou
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Fei Gao
- Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yucheng Lan
- Department of Physics and Engineering Physics, Morgan State University, Baltimore, MD 21251, USA
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36
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Song I, Ahn J, Ahn H, Lee SH, Mei J, Kotov NA, Oh JH. Helical polymers for dissymmetric circularly polarized light imaging. Nature 2023; 617:92-99. [PMID: 37138111 DOI: 10.1038/s41586-023-05877-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 02/22/2023] [Indexed: 05/05/2023]
Abstract
Control of the spin angular momentum (SAM) carried in a photon provides a technologically attractive element for next-generation quantum networks and spintronics1-5. However, the weak optical activity and inhomogeneity of thin films from chiral molecular crystals result in high noise and uncertainty in SAM detection. Brittleness of thin molecular crystals represents a further problem for device integration and practical realization of chiroptical quantum devices6-10. Despite considerable successes with highly dissymmetric optical materials based on chiral nanostructures11-13, the problem of integration of nanochiral materials with optical device platforms remains acute14-16. Here we report a simple yet powerful method to fabricate chiroptical flexible layers via supramolecular helical ordering of conjugated polymer chains. Their multiscale chirality and optical activity can be varied across the broad spectral range by chiral templating with volatile enantiomers. After template removal, chromophores remain stacked in one-dimensional helical nanofibrils producing a homogeneous chiroptical layer with drastically enhanced polarization-dependent absorbance, leading to well-resolved detection and visualization of SAM. This study provides a direct path to scalable realization of on-chip detection of the spin degree of freedom of photons necessary for encoded quantum information processing and high-resolution polarization imaging.
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Affiliation(s)
- Inho Song
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Jaeyong Ahn
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea
| | - Hyungju Ahn
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Sang Hyuk Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea
| | - Jianguo Mei
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Nicholas A Kotov
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, USA.
- Department of Chemical Engineering, Biointerface Institute, University of Michigan, Ann Arbor, MI, USA.
| | - Joon Hak Oh
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, Republic of Korea.
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37
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Chen Z, Liu X, Li X, Gao P, Li Z, Zhu W, Wang H, Li X. Large tunneling magnetoresistance in spin-filtering 1T-MnSe 2/h-BN van der Waals magnetic tunnel junction. NANOSCALE 2023; 15:8447-8455. [PMID: 37097089 DOI: 10.1039/d3nr00045a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The magnetic tunnel junction (MTJ), one of the most prominent spintronic devices, has been widely utilized for memory and computation systems. Electrical writing is considered as a practical method to enhance the performance of MTJs with high circuit integration density and ultralow-power consumption. Meanwhile, a large tunneling magnetoresistance (TMR), especially at the non-equilibrium state, is desirable for the improvement of the sensitivity and stability of MTJ devices. However, achieving both aspects efficiently is still challenging. Here, we propose a two-dimensional (2D) MTJ of 1T-MnSe2/h-BN/1T-MnSe2/h-BN/1T-MnSe2 with efficient electrical writing, reliable reading operations and high potential to work at room temperature. First, for this proposed MTJ with a symmetrical structure and an antiparallel magnetic state, the degeneracy of the energy could be broken by an electric field, resulting in a 180° magnetization reversal. A first principles study confirms that the magnetization of the center 1T-MnSe2 layer could be reversed by changing the direction of the electric field, when the magnetic configurations of the two outer 1T-MnSe2 layers are fixed in the antiparallel state. Furthermore, we report a theoretical spin-related transport investigation of the MTJ at the non-equilibrium state. Thanks to the half-metallicity of 1T-MnSe2, TMR ratios reach very satisfactory values of 2.56 × 103% with the magnetization information written by an electric field at room temperature. In addition, the performance of the TMR effect exhibits good stability even when the bias voltage increases gradually. Our theoretical findings show that this proposed MTJ is a promising high performance spintronic device and could promote the design of ultralow-power spintronic devices.
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Affiliation(s)
- Zhao Chen
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Xiaofeng Liu
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Xingxing Li
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Pengfei Gao
- Interdisciplinary Center for Fundamental and Frontier Sciences, Nanjing University of Science and Technology, Jiangyin, Jiangsu, 214443, China
| | - ZhongJun Li
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, China
| | - Weiduo Zhu
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Haidi Wang
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Xiangyang Li
- School of Materials Science and Engineering, Anhui University, Hefei, Anhui 230601, China
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
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38
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Dao C, Everts JC, Ravnik M, Tserkovnyak Y. Nematronics: Reciprocal Coupling between Ionic Currents and Nematic Dynamics. PHYSICAL REVIEW LETTERS 2023; 130:168102. [PMID: 37154639 DOI: 10.1103/physrevlett.130.168102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 03/31/2023] [Indexed: 05/10/2023]
Abstract
Adopting a spintronics-inspired approach, we study the reciprocal coupling between ionic charge currents and nematic texture dynamics in a uniaxial nematic electrolyte. Assuming quenched fluid dynamics, we develop equations of motion analogously to spin torque and spin pumping. Based on the principle of least dissipation of energy, we derive the adiabatic "nematic torque" exerted by ionic currents on the nematic director field as well as the reciprocal motive force on ions due to the orientational dynamics of the director. We discuss several simple examples that illustrate the potential functionality of this coupling. Furthermore, using our phenomenological framework, we propose a practical means to extract the coupling strength through impedance measurements on a nematic cell. Exploring further applications based on this physics could foster the development of nematronics-nematic iontronics.
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Affiliation(s)
- Chau Dao
- Department of Physics and Astronomy and Bhaumik Institute for Theoretical Physics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Jeffrey C Everts
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Poland
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Miha Ravnik
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia
- Department of Condensed Matter Physics, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Yaroslav Tserkovnyak
- Department of Physics and Astronomy and Bhaumik Institute for Theoretical Physics, University of California, Los Angeles, Los Angeles, California 90095, USA
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39
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García J, Gutiérrez R, González AS, Jiménez-Ramirez AI, Álvarez Y, Vega V, Reith H, Leistner K, Luna C, Nielsch K, Prida VM. Exchange Bias Effect of Ni@(NiO,Ni(OH) 2) Core/Shell Nanowires Synthesized by Electrochemical Deposition in Nanoporous Alumina Membranes. Int J Mol Sci 2023; 24:ijms24087036. [PMID: 37108198 PMCID: PMC10138631 DOI: 10.3390/ijms24087036] [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: 03/14/2023] [Revised: 04/06/2023] [Accepted: 04/09/2023] [Indexed: 04/29/2023] Open
Abstract
Tuning and controlling the magnetic properties of nanomaterials is crucial to implement new and reliable technologies based on magnetic hyperthermia, spintronics, or sensors, among others. Despite variations in the alloy composition as well as the realization of several post material fabrication treatments, magnetic heterostructures as ferromagnetic/antiferromagnetic coupled layers have been widely used to modify or generate unidirectional magnetic anisotropies. In this work, a pure electrochemical approach has been used to fabricate core (FM)/shell (AFM) Ni@(NiO,Ni(OH)2) nanowire arrays, avoiding thermal oxidation procedures incompatible with integrative semiconductor technologies. Besides the morphology and compositional characterization of these core/shell nanowires, their peculiar magnetic properties have been studied by temperature dependent (isothermal) hysteresis loops, thermomagnetic curves and FORC analysis, revealing the existence of two different effects derived from Ni nanowires' surface oxidation over the magnetic performance of the array. First of all, a magnetic hardening of the nanowires along the parallel direction of the applied magnetic field with respect their long axis (easy magnetization axis) has been found. The increase in coercivity, as an effect of surface oxidation, has been observed to be around 17% (43%) at 300 K (50 K). On the other hand, an increasing exchange bias effect on decreasing temperature has been encountered when field cooling (3T) the oxidized Ni@(NiO,Ni(OH)2) nanowires below 100 K along their parallel lengths.
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Affiliation(s)
- Javier García
- Departamento de Física, Facultad de Ciencias, Universidad de Oviedo, C/Federico García Lorca 18, 33007 Oviedo, Spain
| | - Ruth Gutiérrez
- Departamento de Física, Facultad de Ciencias, Universidad de Oviedo, C/Federico García Lorca 18, 33007 Oviedo, Spain
| | - Ana S González
- Departamento de Física, Facultad de Ciencias, Universidad de Oviedo, C/Federico García Lorca 18, 33007 Oviedo, Spain
| | - Ana I Jiménez-Ramirez
- Departamento de Física, Facultad de Ciencias, Universidad de Oviedo, C/Federico García Lorca 18, 33007 Oviedo, Spain
| | - Yolanda Álvarez
- Departamento de Física, Facultad de Ciencias, Universidad de Oviedo, C/Federico García Lorca 18, 33007 Oviedo, Spain
| | - Víctor Vega
- Laboratorio de Membranas Nanoporosas, Edificio de Servicios Científico Técnicos "Severo Ochoa", Universidad de Oviedo, C/Fernando Bonguera s/n, 33006 Oviedo, Spain
| | - Heiko Reith
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Karin Leistner
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
- Electrochemical Sensors and Energy Storage, Faculty of Natural Sciences, Institute of Chemistry, TU Chemnitz, Strasse der Nationen 62, 09111 Chemnitz, Germany
| | - Carlos Luna
- Facultad de Ciencias Físico Matemáticas (FCFM), Universidad Autónoma de Nuevo León (UANL), Av. Universidad S/N, San Nicolás de los Garza 66455, Nuevo León, Mexico
| | - Kornelius Nielsch
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Víctor M Prida
- Departamento de Física, Facultad de Ciencias, Universidad de Oviedo, C/Federico García Lorca 18, 33007 Oviedo, Spain
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40
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Wang C, Shi G, Qiao F, Lin R, Wu S, Hu Z. Research progress in architecture and application of RRAM with computing-in-memory. NANOSCALE ADVANCES 2023; 5:1559-1573. [PMID: 36926563 PMCID: PMC10012847 DOI: 10.1039/d3na00025g] [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: 01/11/2023] [Accepted: 02/04/2023] [Indexed: 06/18/2023]
Abstract
The development of new technologies has led to an explosion of data, while the computation ability of traditional computers is approaching its upper limit. The dominant system architecture is the von Neumann architecture, with the processing and storage units working independently. The data migrate between them via buses, reducing computing speed and increasing energy loss. Research is underway to increase computing power, such as developing new chips and adopting new system architectures. Computing-in-memory (CIM) technology allows data to be computed directly on the memory, changing the current computation-centric architecture and designing a new storage-centric architecture. Resistive random access memory (RRAM) is one of the advanced memories which has appeared in recent years. RRAM can change its resistance with electrical signals at both ends, and the state will be preserved after power-down. It has potential in logic computing, neural networks, brain-like computing, and fused technology of sense-storage-computing. These advanced technologies promise to break the performance bottleneck of traditional architectures and dramatically increase computing power. This paper introduces the basic concepts of computing-in-memory technology and the principle and applications of RRAM and finally gives a conclusion about these new technologies.
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Affiliation(s)
- Chenyu Wang
- College of Mechanical and Electrical Engineering, China Jiliang University Hangzhou China
| | - Ge Shi
- College of Mechanical and Electrical Engineering, China Jiliang University Hangzhou China
| | - Fei Qiao
- Dept of Electronic Engineering, Tsinghua University Beijing 310018 People's Republic of China
| | - Rubin Lin
- College of Mechanical and Electrical Engineering, China Jiliang University Hangzhou China
| | - Shien Wu
- College of Mechanical and Electrical Engineering, China Jiliang University Hangzhou China
| | - Zenan Hu
- College of Mechanical and Electrical Engineering, China Jiliang University Hangzhou China
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41
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Guo S, Wang B, Wolf D, Lubk A, Xia W, Wang M, Xiao Y, Cui J, Pravarthana D, Dou Z, Leistner K, Li RW, Hühne R, Nielsch K. Hierarchically Engineered Manganite Thin Films with a Wide-Temperature-Range Colossal Magnetoresistance Response. ACS NANO 2023; 17:2517-2528. [PMID: 36651833 DOI: 10.1021/acsnano.2c10200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Colossal magnetoresistance is of great fundamental and technological significance in condensed-matter physics, magnetic memory, and sensing technologies. However, its relatively narrow working temperature window is still a severe obstacle for potential applications due to the nature of the material-inherent phase transition. Here, we realized hierarchical La0.7Sr0.3MnO3 thin films with well-defined (001) and (221) crystallographic orientations by combining substrate modification with conventional thin-film deposition. Microscopic investigations into its magnetic transition through electron holography reveal that the hierarchical microstructure significantly broadens the temperature range of the ferromagnetic-paramagnetic transition, which further widens the response temperature range of the macroscopic colossal magnetoresistance under the scheme of the double-exchange mechanism. Therefore, this work puts forward a method to alter the magnetic transition and thus to extend the magnetoresistance working window by nanoengineering, which might be a promising approach also for other phase-transition-related effects in functional oxides.
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Affiliation(s)
- Shanshan Guo
- CAS Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People's Republic of China
- Leibniz IFW Dresden, Dresden 01069, Germany
| | - Baomin Wang
- CAS Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People's Republic of China
- School of Physical Science and Technology, Ningbo University, Ningbo 315201, People's Republic of China
| | | | - Axel Lubk
- Leibniz IFW Dresden, Dresden 01069, Germany
- Institute of Solid State and Materials Physics, TU Dresden, Dresden 01069, Germany
| | - Weixing Xia
- CAS Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People's Republic of China
| | - Mingkun Wang
- CAS Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People's Republic of China
| | - Yao Xiao
- CAS Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People's Republic of China
| | - Junfeng Cui
- Key Laboratory of Marine Materials and Related Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People's Republic of China
| | - Dhanapal Pravarthana
- CAS Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People's Republic of China
| | - Zehua Dou
- Leibniz IFW Dresden, Dresden 01069, Germany
| | - Karin Leistner
- Leibniz IFW Dresden, Dresden 01069, Germany
- Electrochemical Sensors and Energy Storage, Faculty of Natural Sciences, Institute of Chemistry, TU Chemnitz, Chemnitz 09111, Germany
| | - Run-Wei Li
- CAS Key Laboratory of Magnetic Materials and Devices, Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People's Republic of China
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42
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Anyfantis DI, Ballani C, Kanistras N, Barnasas A, Tsiaoussis I, Schmidt G, Papaioannou ET, Poulopoulos P. Magnetic Anisotropies and Exchange Bias of Co/CoO Multilayers with Intermediate Ultrathin Pt Layers. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1378. [PMID: 36837008 PMCID: PMC9963626 DOI: 10.3390/ma16041378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/30/2023] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
Co/CoO multilayers are fabricated by means of radio-frequency magnetron sputtering. For the formation of each multilayer period, a Co layer is initially produced followed by natural oxidation. Platinum is used not only as buffer and capping layers, but also in the form of intermediate ultrathin layers to enhance perpendicular magnetic anisotropy. Three samples are compared with respect to the magnetic anisotropies and exchange bias between 4-300 K based on superconducting quantum interference device magnetometry measurements. Two of the multilayers are identical Co/CoO/Pt ones; one of them, however, is grown on a Co/Pt "magnetic substrate" to induce perpendicular magnetic anisotropy via exchange coupling through an ultrathin Pt intermediate layer. The third multilayer is of the form Co/CoO/Co/Pt. The use of a "magnetic substrate" results in the observation of loops with large remanence when the field applies perpendicular to the film plane. The CoO/Co interfaces lead to a significant exchange bias at low temperatures after field cooling. The largest exchange bias was observed in the film with double Co/CoO/Co interfaces. Consequently, significant perpendicular anisotropy coexists with large exchange bias, especially at low temperatures. Such samples can be potentially useful for applications related to spintronics and magnetic storage.
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Affiliation(s)
- Dimitrios I. Anyfantis
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece
| | - Camillo Ballani
- Institut für Physik, Martin-Luther Universität Halle Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle, Germany
| | - Nikos Kanistras
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece
- Institut für Physik, Martin-Luther Universität Halle Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle, Germany
| | - Alexandros Barnasas
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece
| | - Ioannis Tsiaoussis
- Department of Physics, School of Natural Sciences, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Georg Schmidt
- Institut für Physik, Martin-Luther Universität Halle Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle, Germany
- Interdisziplinäres Zentrum für Materialwissenschaften, Nanotechnikum Weinberg, Martin-Luther University Halle-Wittenberg, 06120 Halle, Germany
| | - Evangelos Th. Papaioannou
- Institut für Physik, Martin-Luther Universität Halle Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle, Germany
| | - Panagiotis Poulopoulos
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece
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43
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Yu D, Ga Y, Liang J, Jia C, Yang H. Voltage-Controlled Dzyaloshinskii-Moriya Interaction Torque Switching of Perpendicular Magnetization. PHYSICAL REVIEW LETTERS 2023; 130:056701. [PMID: 36800473 DOI: 10.1103/physrevlett.130.056701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/30/2022] [Accepted: 12/20/2022] [Indexed: 06/18/2023]
Abstract
Magnetization switching is the most important operation in spintronic devices. In modern nonvolatile magnetic random-access memory (MRAM), it is usually realized by spin-transfer torque (STT) or spin-orbit torque (SOT). However, both STT and SOT MRAM require current to drive magnetization switching, which will cause Joule heating. Here, we report an alternative mechanism, Dzyaloshinskii-Moriya interaction (DMI) torque, that can realize magnetization switching fully controlled by voltage pulses. We find that a consequential voltage-controlled reversal of DMI chirality in multiferroics can lead to continued expansion of a skyrmion thanks to the DMI torque. Enough DMI torque will eventually make the skyrmion burst into a quasiuniform ferromagnetic state with reversed magnetization, thus realizing the switching of a perpendicular magnet. The discovery is demonstrated in two-dimensional multiferroics, CuCrP_{2}Se_{6} and CrN, using first-principles calculations and micromagnetic simulations. As an example, we applied the DMI torque for simulating leaky-integrate-fire functionality of biological neurons. Our discovery of DMI torque switching of perpendicular magnetization provides tremendous potential toward magnetic-field-free and current-free spintronic devices, and neuromorphic computing as well.
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Affiliation(s)
- Dongxing Yu
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Yonglong Ga
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Jinghua Liang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Chenglong Jia
- Key Laboratory for Magnetism and Magnetic Materials of MOE and Lanzhou Center for Theoretical Physics, 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
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
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44
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Wang X, Zhuang Q, Wu P, Liu L, Wang F, Zhang X, Li X, Zheng X. Tweezer-like magnetic tip control of the local spin state in the FeOEP/Pb(111) adsorption system: a preliminary exploration based on first-principles calculations. NANOSCALE 2023; 15:2369-2376. [PMID: 36648279 DOI: 10.1039/d2nr04379c] [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
The magnetic interactions between the spin-polarized scanning tunnelling microscopy (SP-STM) tip and the localized spin impurities lead to various forms of the Kondo effect. Although these intriguing phenomena enrich Kondo physics, detailed theoretical simulations and explanations are still lacking due to the rather complex formation mechanisms. Here, by combining density functional theory (DFT), complete active space self-consistent field (CASSCF) theory, and hierarchical equations of motion (HEOM) methods, we perform first-principles-based simulation to elaborate the regulation process of the magnetic Co-tip on the spin state and transport behaviour of FeOEP/Pb(111) system. Compared with the non-magnetic tip, the stronger interaction between the magnetic tip and FeOEP molecule results in a more drastic deformation of the molecular structure with more electron transfer from the local environment to Fe-3d orbitals. The magnetic anisotropy of FeOEP changes very drastically from positive values in the tunnelling region to negative values in the contact region. The ferromagnetic electron correlation between the magnetic tip and the molecule induces an asymmetric Kondo line-shape near the Fermi level. This work highlights that the DFT + CASSCF + HEOM approach can not only predict complex quantum phenomena and explain underlying physical mechanisms, but also facilitate the design of more fascinating quantum control experiments.
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Affiliation(s)
- Xiaoli Wang
- College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, China
| | - Qingfeng Zhuang
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Ping Wu
- College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, China
| | - Leifang Liu
- College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, China
| | - Fang Wang
- College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, China
| | - Xiaolei Zhang
- College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, China
| | - Xiangyang Li
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Xiao Zheng
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
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45
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Chen L, Yang S, Dotzert M, Melling CWJ, Zhang J. Hybrid reduced graphene oxide nanosheets with negative magnetoresistance for the diagnosis of hypoglycemia. J Mater Chem B 2023; 11:998-1007. [PMID: 36621800 DOI: 10.1039/d2tb01927b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Few glucometers are available to easily and quickly measure low blood glucose levels (≤4 mmol L-1) from a small amount of blood samples. Here, a hybrid reduced graphene oxide (rGO)-based magnetoresistance (MR) sensor has been developed to monitor blood glucose levels to quickly detect hypoglycemia. Hybrid rGO nanosheets, incorporating Fe50Co50 nanoparticles onto rGO nanosheets, with an unusual large negative MR (-5.7%) at room temperature under a small magnetic field (9.5 kOe) have been successfully fabricated through a one-pot reaction. To quickly detect the low concentration of glucose in a small amount of blood (1 μL), a two-step process has been further developed by using the "sandwich" structural MR sensor. The results show that the higher the negative MR value of the sensor, the lower the concentration of glucose that can be detected. A linear relationship between the MR and the concentration of the spiked plasma glucose taken from streptozotocin-induced diabetic rats can be found when the concentration of glucose is in the range of 0-6 mmol L-1. The limit of detection (LOD) of this MR glucose sensor is 0.867 mmol L-1. The accuracy of the rGO-based MR sensor is improved in measuring low concentration of plasma glucose as compared to that of a commercialized glucometer. Furthermore, the selectivity of the rGO-based MR sensor has been studied. The results demonstrate that the rGO-based MR sensor is a flexible and sensitive detection platform and specifically suitable for monitoring low concentrations of plasma glucose to prevent from hypoglycemia.
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Affiliation(s)
- Longyi Chen
- Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario, N6A 5B9, Canada.
| | - Songlin Yang
- Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario, N6A 5B9, Canada.
| | - Michelle Dotzert
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, N6A 5B9, Canada
| | - C W James Melling
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, N6A 5B9, Canada
| | - Jin Zhang
- Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario, N6A 5B9, Canada. .,School of Biomedical Engineering, University of Western Ontario, London, Ontario, N6A 5B9, Canada
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46
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Liu D, Liu Z, Zhang J, Yin Y, Xi J, Wang L, Xiong J, Zhang M, Zhao T, Jin J, Hu F, Sun J, Shen J, Shen B. Classification and Prediction of Skyrmion Material Based on Machine Learning. RESEARCH (WASHINGTON, D.C.) 2023; 6:0082. [PMID: 36939441 PMCID: PMC10019916 DOI: 10.34133/research.0082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 02/08/2023] [Indexed: 02/12/2023]
Abstract
The discovery and study of skyrmion materials play an important role in basic frontier physics research and future information technology. The database of 196 materials, including 64 skyrmions, was established and predicted based on machine learning. A variety of intrinsic features are classified to optimize the model, and more than a dozen methods had been used to estimate the existence of skyrmion in magnetic materials, such as support vector machines, k-nearest neighbor, and ensembles of trees. It is found that magnetic materials can be more accurately divided into skyrmion and non-skyrmion classes by using the classification of electronic layer. Note that the rare earths are the key elements affecting the production of skyrmion. The accuracy and reliability of random undersampling bagged trees were 87.5% and 0.89, respectively, which have the potential to build a reliable machine learning model from small data. The existence of skyrmions in LaBaMnO is predicted by the trained model and verified by micromagnetic theory and experiments.
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Affiliation(s)
- Dan Liu
- Department of Physics, School of Artificial Intelligence,
Beijing Technology and Business University, Beijing 100048, P. R. China
- Address correspondence to:
| | - Zhixin Liu
- Department of Physics, School of Artificial Intelligence,
Beijing Technology and Business University, Beijing 100048, P. R. China
| | - JinE Zhang
- School of Integrated Circuit Science and Engineering,
Beihang University, Beijing 100191, China
| | - Yinong Yin
- Department of Physics, School of Artificial Intelligence,
Beijing Technology and Business University, Beijing 100048, P. R. China
| | - Jianfeng Xi
- Department of Physics, School of Artificial Intelligence,
Beijing Technology and Business University, Beijing 100048, P. R. China
| | - Lichen Wang
- Ningbo Institute of Materials, Technology & Engineering,
Chinese Academy of Sciences, Zhejiang 315201, P. R. China
| | - JieFu Xiong
- Ningbo Institute of Materials, Technology & Engineering,
Chinese Academy of Sciences, Zhejiang 315201, P. R. China
| | - Ming Zhang
- School of Physics,
Inner Mongolia University of Science and Technology, Baotou 014010, P. R. China
| | - Tongyun Zhao
- State Key Laboratory of Magnetism, Institute of Physics,
Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Jiaying Jin
- School of Materials Science and Engineering,
Zhejiang University, Hangzhou 310027, P. R. China
| | - Fengxia Hu
- State Key Laboratory of Magnetism, Institute of Physics,
Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Jirong Sun
- State Key Laboratory of Magnetism, Institute of Physics,
Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Jun Shen
- Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry,
Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Baogen Shen
- Ningbo Institute of Materials, Technology & Engineering,
Chinese Academy of Sciences, Zhejiang 315201, P. R. China
- State Key Laboratory of Magnetism, Institute of Physics,
Chinese Academy of Sciences, Beijing 100190, P. R. China
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47
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Chen X, Higo T, Tanaka K, Nomoto T, Tsai H, Idzuchi H, Shiga M, Sakamoto S, Ando R, Kosaki H, Matsuo T, Nishio-Hamane D, Arita R, Miwa S, Nakatsuji S. Octupole-driven magnetoresistance in an antiferromagnetic tunnel junction. Nature 2023; 613:490-495. [PMID: 36653566 PMCID: PMC9849134 DOI: 10.1038/s41586-022-05463-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 10/19/2022] [Indexed: 01/19/2023]
Abstract
The tunnelling electric current passing through a magnetic tunnel junction (MTJ) is strongly dependent on the relative orientation of magnetizations in ferromagnetic electrodes sandwiching an insulating barrier, rendering efficient readout of spintronics devices1-5. Thus, tunnelling magnetoresistance (TMR) is considered to be proportional to spin polarization at the interface1 and, to date, has been studied primarily in ferromagnets. Here we report observation of TMR in an all-antiferromagnetic tunnel junction consisting of Mn3Sn/MgO/Mn3Sn (ref. 6). We measured a TMR ratio of around 2% at room temperature, which arises between the parallel and antiparallel configurations of the cluster magnetic octupoles in the chiral antiferromagnetic state. Moreover, we carried out measurements using a Fe/MgO/Mn3Sn MTJ and show that the sign and direction of anisotropic longitudinal spin-polarized current in the antiferromagnet7 can be controlled by octupole direction. Strikingly, the TMR ratio (about 2%) of the all-antiferromagnetic MTJ is much larger than that estimated using the observed spin polarization. Theoretically, we found that the chiral antiferromagnetic MTJ may produce a substantially large TMR ratio as a result of the time-reversal, symmetry-breaking polarization characteristic of cluster magnetic octupoles. Our work lays the foundation for the development of ultrafast and efficient spintronic devices using antiferromagnets8-10.
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Affiliation(s)
- Xianzhe Chen
- Department of Physics, University of Tokyo, Tokyo, Japan.,Institute for Solid State Physics, University of Tokyo, Chiba, Japan
| | - Tomoya Higo
- Department of Physics, University of Tokyo, Tokyo, Japan.,Institute for Solid State Physics, University of Tokyo, Chiba, Japan.,CREST, Japan Science and Technology Agency, Saitama, Japan
| | - Katsuhiro Tanaka
- Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, Japan
| | - Takuya Nomoto
- Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, Japan.,PRESTO, Japan Science and Technology Agency, Saitama, Japan
| | - Hanshen Tsai
- Department of Physics, University of Tokyo, Tokyo, Japan.,Institute for Solid State Physics, University of Tokyo, Chiba, Japan
| | - Hiroshi Idzuchi
- Department of Physics, University of Tokyo, Tokyo, Japan.,Institute for Solid State Physics, University of Tokyo, Chiba, Japan
| | - Masanobu Shiga
- Institute for Solid State Physics, University of Tokyo, Chiba, Japan
| | - Shoya Sakamoto
- Institute for Solid State Physics, University of Tokyo, Chiba, Japan
| | - Ryoya Ando
- Institute for Solid State Physics, University of Tokyo, Chiba, Japan
| | - Hidetoshi Kosaki
- Institute for Solid State Physics, University of Tokyo, Chiba, Japan
| | - Takumi Matsuo
- Department of Physics, University of Tokyo, Tokyo, Japan
| | | | - Ryotaro Arita
- CREST, Japan Science and Technology Agency, Saitama, Japan.,Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, Japan.,RIKEN, Center for Emergent Matter Science, Saitama, Japan
| | - Shinji Miwa
- Institute for Solid State Physics, University of Tokyo, Chiba, Japan.,CREST, Japan Science and Technology Agency, Saitama, Japan.,Trans-scale Quantum Science Institute, University of Tokyo, Tokyo, Japan
| | - Satoru Nakatsuji
- Department of Physics, University of Tokyo, Tokyo, Japan. .,Institute for Solid State Physics, University of Tokyo, Chiba, Japan. .,CREST, Japan Science and Technology Agency, Saitama, Japan. .,Trans-scale Quantum Science Institute, University of Tokyo, Tokyo, Japan. .,Canadian Institute for Advanced Research, Toronto, Ontario, Canada.
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48
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Biswas A, Mitra SP, Bhowmick R, Adak D, Chattopadhyaya M, Sen S. Spintronic Action of Cn-C6H6-Fe-C6H6-C13-n; n=6: how crucial are d electrons? J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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49
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Causal analysis and visualization of magnetization reversal using feature extended landau free energy. Sci Rep 2022; 12:19892. [DOI: 10.1038/s41598-022-21971-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 10/06/2022] [Indexed: 11/30/2022] Open
Abstract
AbstractThe magnetization reversal in nanomagnets is causally analyzed using an extended Landau free-energy model. This model draws an energy landscape in the information space using physics-based features. Thus, the origin of the magnetic effect in macroscopic pinning phenomena can be identified. The microscopic magnetic domain beyond the hierarchy can be explained using energy gradient analysis and its decomposition. Structural features from the magnetic domains are extracted using persistent homology. Extended energy is visualized using ridge regression, principal component analysis, and Hadamard products. We found that the demagnetization energy concentration near a defect causes the demagnetization effect, which quantitatively dominates the pinning phenomenon. The exchange energy inhibits pinning, promotes saturation, and shows slight interactions with the defect. Furthermore, the energy distributions are visualized in real space. Left-position defects reduce the energy barrier and are useful for the topological inverse design of recording devices.
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50
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Review on Magnetism in Catalysis: From Theory to PEMFC Applications of 3d Metal Pt-Based Alloys. Int J Mol Sci 2022; 23:ijms232314768. [PMID: 36499096 PMCID: PMC9739051 DOI: 10.3390/ijms232314768] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/18/2022] [Accepted: 11/22/2022] [Indexed: 11/29/2022] Open
Abstract
The relationship between magnetism and catalysis has been an important topic since the mid-20th century. At present time, the scientific community is well aware that a full comprehension of this relationship is required to face modern challenges, such as the need for clean energy technology. The successful use of (para-)magnetic materials has already been corroborated in catalytic processes, such as hydrogenation, Fenton reaction and ammonia synthesis. These catalysts typically contain transition metals from the first to the third row and are affected by the presence of an external magnetic field. Nowadays, it appears that the most promising approach to reach the goal of a more sustainable future is via ferromagnetic conducting catalysts containing open-shell metals (i.e., Fe, Co and Ni) with extra stabilization coming from the presence of an external magnetic field. However, understanding how intrinsic and extrinsic magnetic features are related to catalysis is still a complex task, especially when catalytic performances are improved by these magnetic phenomena. In the present review, we introduce the relationship between magnetism and catalysis and outline its importance in the production of clean energy, by describing the representative case of 3d metal Pt-based alloys, which are extensively investigated and exploited in PEM fuel cells.
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