1
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Deng Y, Wang M, Xiang Z, Zhu K, Hu T, Lu L, Wang Y, Ma Y, Lei B, Chen X. Room-Temperature Highly Efficient Nonvolatile Magnetization Switching by Current in van der Waals Fe 3GaTe 2 Devices. NANO LETTERS 2024. [PMID: 39017705 DOI: 10.1021/acs.nanolett.4c02227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
The ability to manipulate magnetic states by a low electric current represents a fundamental desire in spintronics. In recent years, two-dimensional van der Waals (vdW) magnetic materials have attracted an extensive amount of attention due to their appreciable spin-orbit torque effect. However, for most known vdW ferromagnets, their relatively low Curie temperatures (TC) limit their applications. Consequently, low-power vdW spintronic devices that can operate at room temperature are in great demand. In this research, we fabricate nanodevices based on a solitary thin flake of vdW ferromagnet Fe3GaTe2, in which we successfully achieve nonvolatile and highly efficient magnetization switching by small currents at room temperature. Notably, the switching current density and the switching power dissipation are as low as 1.7 × 105 A/cm2 and 1.6 × 1013 W/m3, respectively, with an external magnetic field of 80 Oe; both are much reduced compared to those of conventional magnet/heavy metal heterostructure devices and other vdW devices.
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Affiliation(s)
- Yazhou Deng
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Mingjie Wang
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Ziji Xiang
- CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Kejia Zhu
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Tao Hu
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Longyu Lu
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Yu Wang
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Yupeng Ma
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Bin Lei
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Xianhui Chen
- CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei, Anhui 230026, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, China
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2
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Ding S, Kang MG, Legrand W, Gambardella P. Orbital Torque in Rare-Earth Transition-Metal Ferrimagnets. PHYSICAL REVIEW LETTERS 2024; 132:236702. [PMID: 38905652 DOI: 10.1103/physrevlett.132.236702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 01/13/2024] [Accepted: 05/08/2024] [Indexed: 06/23/2024]
Abstract
Orbital currents have recently emerged as a promising tool to achieve electrical control of the magnetization in thin-film ferromagnets. Efficient orbital-to-spin conversion is required in order to torque the magnetization. Here, we show that the injection of an orbital current in a ferrimagnetic Gd_{y}Co_{100-y} alloy generates strong orbital torques whose sign and magnitude can be tuned by changing the Gd content and temperature. The effective spin-orbital Hall angle reaches up to -0.25 in a Gd_{y}Co_{100-y}/CuO_{x} bilayer compared to +0.03 in Co/CuO_{x} and +0.13 in Gd_{y}Co_{100-y}/Pt. This behavior is attributed to the local orbital-to-spin conversion taking place at the Gd sites, which is about 5 times stronger and of the opposite sign relative to Co. Furthermore, we observe a manyfold increase in the net orbital torque at low temperature, which we attribute to the improved conversion efficiency following the magnetic ordering of the Gd and Co sublattices.
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3
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Moriya H, Taniguchi M, Jo D, Go D, Soya N, Hayashi H, Mokrousov Y, Lee HW, Ando K. Observation of Long-Range Current-Induced Torque in Ni/Pt Bilayers. NANO LETTERS 2024; 24:6459-6464. [PMID: 38780051 DOI: 10.1021/acs.nanolett.3c05102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
The generation of current-induced torques through the spin Hall effect in Pt has been key to the development of spintronics. In prototypical ferromagnetic-metal/Pt devices, the characteristic length of the torque generation is known to be about 1 nm due to the short spin diffusion length of Pt. Here, we report the observation of a long-range current-induced torque in Ni/Pt bilayers. We demonstrate that when Ni is used as the ferromagnetic layer, the torque efficiency increases with the Pt thickness, even when it exceeds 10 nm. The torque efficiency is also enhanced by increasing the Ni thickness, providing evidence that the observed torque cannot be attributed to the spin Hall effect in the Pt layer. These findings, coupled with our semirealistic tight-binding calculations of the current-induced torque, suggest the possibility that the observed long-range torque is dominated by the orbital Hall effect in the Pt layer.
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Affiliation(s)
- Hiroyuki Moriya
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan
| | - Mari Taniguchi
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan
| | - Daegeun Jo
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Dongwook Go
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
- Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Nozomi Soya
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan
| | - Hiroki Hayashi
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan
- Keio Institute of Pure and Applied Sciences, Keio University, Yokohama 223-8522, Japan
| | - Yuriy Mokrousov
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
- Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Hyun-Woo Lee
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Kazuya Ando
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan
- Keio Institute of Pure and Applied Sciences, Keio University, Yokohama 223-8522, Japan
- Center for Spintronics Research Network, Keio University, Yokohama 223-8522, Japan
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4
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Xie Z, Yang Y, Chen B, Zhao Z, Qin H, Sun H, Lei N, Zhao J, Wei D. Giant Spin-Orbit Torque in Antiferromagnetic-Coupled Pt/[Co/Gd] N Multilayers with Suppressed Spin Dephasing and Robust Thermal Stability. ACS APPLIED MATERIALS & INTERFACES 2024; 16:27944-27951. [PMID: 38764370 DOI: 10.1021/acsami.4c04273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2024]
Abstract
Manipulating magnetization via power-efficient spin-orbit torque (SOT) has garnered significant attention in the field of spin-based memory and logic devices. However, the damping-like SOT efficiency (ξDL) in heavy metal (HM)/ferromagnetic metal (FM) bilayers is relatively small due to the strong spin dephasing accompanied by additional spin polarization decay. Furthermore, the perpendicular magnetic anisotropy (PMA) originating from the HM/FM interface is constrained by the thickness of FM, which is unfavorable for thermal stability in practical applications. Consequently, it is valuable to develop systems that not only exhibit large ξDL but also balance thermal stability. In this work, we designed antiferromagnetic-coupled [Co/Gd]N multilayers, where staggered Co and Gd magnetic moments effectively suppress the spin dephasing and additional spin polarization decay. The ordered Co-Gd arrangements along the out-of-plane direction provide bulk PMA, endowing Pt/[Co/Gd]N high thermal stability. The SOT of Pt/[Co/Gd]N was systematically studied with N, demonstrating a significantly large ξDL of up to 0.66. The ξDL of Pt/[Co/Gd]N is greater than those of Pt/Co and Pt/ferrimagnetic alloys. This significant enhancement relies on the effective suppression of spin dephasing in [Co/Gd]N. Our work highlights that the antiferromagnetic-coupled [Co/Gd]N multilayer is a promising candidate for low-consumption and high-density spintronic devices.
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Affiliation(s)
- Zhicheng Xie
- State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Yumin Yang
- State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Bingyu Chen
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
| | - Zhiyuan Zhao
- State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Hongrui Qin
- State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Hongli Sun
- State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Na Lei
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
| | - Jianhua Zhao
- State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Dahai Wei
- State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100190, China
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Zhang KX, Xu H, Keum J, Wang X, Liu M, Chen Z. Unexpected versatile electrical transport behaviors of ferromagnetic nickel films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:235801. [PMID: 38417165 DOI: 10.1088/1361-648x/ad2e25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 02/28/2024] [Indexed: 03/01/2024]
Abstract
Perpendicular magnetic anisotropy (PMA) of magnets is paramount for electrically controlled spintronics due to their intrinsic potentials for higher memory density, scalability, thermal stability and endurance, surpassing an in-plane magnetic anisotropy (IMA). Nickel film is a long-lived fundamental element ferromagnet, yet its electrical transport behavior associated with magnetism has not been comprehensively studied, hindering corresponding spintronic applications exploiting nickel-based compounds. Here, we systematically investigate the highly versatile magnetism and corresponding transport behavior of nickel films. As the thickness reduces within the general thickness regime of a magnet layer for a memory device, the hardness of nickel films' ferromagnetic loop of anomalous Hall effect increases and then decreases, reflecting the magnetic transitions from IMA to PMA and back to IMA. Additionally, the square ferromagnetic loop changes from a hard to a soft one at rising temperatures, indicating a shift from PMA to IMA. Furthermore, we observe a butterfly magnetoresistance resulting from the anisotropic magnetoresistance effect, which evolves in conjunction with the thickness and temperature-dependent magnetic transformations as a complementary support. Our findings unveil the rich magnetic dynamics and most importantly settle down the most useful guiding information for current-driven spintronic applications based on nickel film: The hysteresis loop is squarest for the ∼8 nm-thick nickel film, of highest hardness withRxyr/Rxys∼ 1 and minimumHs-Hc, up to 125 K; otherwise, extra care should be taken for a different thickness or at a higher temperature.
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Affiliation(s)
- Kai-Xuan Zhang
- Center for Quantum Materials, Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea
| | - Hanshu Xu
- Department of Applied Physics, School of Biomedical Engineering, Anhui Medical University, Hefei 230032, People's Republic of China
| | - Jihoon Keum
- Center for Quantum Materials, Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea
| | - Xiangqi Wang
- Jihua Laboratory Testing Center, Jihua Laboratory, Foshan 528000, People's Republic of China
| | - Meizhuang Liu
- School of Semiconductor Science and Technology, South China Normal University, Foshan 528225, People's Republic of China
| | - Zuxin Chen
- School of Semiconductor Science and Technology, South China Normal University, Foshan 528225, People's Republic of China
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, Guangzhou 510631, People's Republic of China
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6
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Zhang Y, Xu T, Jiang W, Yu R, Chen Z. Quantification of Hybrid Topological Spin Textures and Their Nanoscale Fluctuations in Ferrimagnets. NANO LETTERS 2024; 24:2727-2734. [PMID: 38395052 DOI: 10.1021/acs.nanolett.3c04409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
Noncolinear spin textures, including chiral stripes and skyrmions, have shown great potential in spintronics. Basic configurations of spin textures are either Bloch or Néel types, and the intermediate hybrid type has rarely been reported. A major challenge in identifying hybrid spin textures is to quantitatively determine the hybrid angle, especially in ferrimagnets with weak net magnetization. Here, we develop an approach to quantify magnetic parameters, including chirality, saturation magnetization, domain wall width, and hybrid angle with sub-5 nm spatial resolution, based on Lorentz four-dimensional scanning transmission electron microscopy (Lorentz 4D-STEM). We find strong nanometer-scale variations in the hybrid angle and domain wall width within structurally and chemically homogeneous FeGd ferrimagnetic films. These variations fluctuate during different magnetization circles, revealing intrinsic local magnetization inhomogeneities. Furthermore, hybrid skyrmions can also be nucleated in FeGd films. These analyses demonstrate that the Lorentz 4D-STEM is a quantitative tool for exploring complex spin textures.
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Affiliation(s)
- Yuxuan Zhang
- School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
- MOE Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084, China
- State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084, China
| | - Teng Xu
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Wanjun Jiang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Rong Yu
- School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
- MOE Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084, China
- State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084, China
| | - Zhen Chen
- 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
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7
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Dou P, Zhang J, Guo Y, Zhu T, Luo J, Zhao G, Huang H, Yu G, Zhao Y, Qi J, Deng X, Wang Y, Li J, Shen J, Zheng X, Wu Y, Yang H, Shen B, Wang S. Deterministic Magnetization Switching via Tunable Noncollinear Spin Configurations in Canted Magnets. NANO LETTERS 2023. [PMID: 37379096 DOI: 10.1021/acs.nanolett.3c01192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Spin obit torque (SOT) driven magnetization switching has been used widely for encoding consumption-efficient memory and logic. However, symmetry breaking under a magnetic field is required to realize the deterministic switching in synthetic antiferromagnets with perpendicular magnetic anisotropy (PMA), which limits their potential applications. Herein, we report all electric-controlled magnetization switching in the antiferromagnetic Co/Ir/Co trilayers with vertical magnetic imbalance. Besides, the switching polarity could be reversed by optimizing the Ir thickness. By using the polarized neutron reflection (PNR) measurements, the canted noncollinear spin configuration was observed in Co/Ir/Co trilayers, which results from the competition of magnetic inhomogeneity. In addition, the asymmetric domain walls demonstrated by micromagnetic simulations result from introducing imbalance magnetism, leading to the deterministic magnetization switching in Co/Ir/Co trilayers. Our findings highlight a promising route to electric-controlled magnetism via tunable spin configuration, improve our understanding of physical mechanisms, and significantly promote industrial applications in spintronic devices.
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Affiliation(s)
- Pengwei Dou
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jingyan Zhang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yaqin Guo
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Tao Zhu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jia Luo
- College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610068, China
| | - Guoping Zhao
- College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610068, China
| | - He Huang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yunchi Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jie Qi
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xiao Deng
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yuanbo Wang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jialiang Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jianxin Shen
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xinqi Zheng
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yanfei Wu
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Hongxin Yang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shouguo Wang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
- School of Materials Science and Engineering, Anhui University, Hefei 230601, China
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Ren L, Zhou C, Song X, Seng HT, Liu L, Li C, Zhao T, Zheng Z, Ding J, Feng YP, Chen J, Teo KL. Efficient Spin-Orbit Torque Switching in a Perpendicularly Magnetized Heusler Alloy MnPtGe Single Layer. ACS NANO 2023; 17:6400-6409. [PMID: 36942968 DOI: 10.1021/acsnano.2c11132] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Electrically manipulating magnetic moments by spin-orbit torque (SOT) has great potential applications in magnetic memories and logic devices. Although there have been rich SOT studies on magnetic heterostructures, low interfacial thermal stability and high switching current density still remain an issue. Here, highly textured, polycrystalline Heusler alloy MnxPtyGe (MPG) films with various thicknesses are directly deposited onto thermally oxidized silicon wafers. The perpendicular magnetization of the MPG single layer can be reversibly switched by electrical current pulses with a magnitude as low as 4.1 × 1010Am-2, as evidenced by both the electrical transport and the magnetic optical measurements. The switching is shown to arise from inversion symmetry breaking due to the vertical composition gradient of the films after sample annealing. The SOT effective fields of the samples are analyzed systematically. It is found that the SOT efficiency increases with the film thickness, suggesting a robust bulk-like behavior in the single magnetic layer. Furthermore, a memristive characteristic has been observed due to a multidomain switching property in the single-layer MPG device. Additionally, deterministic field-free switching of magnetization is observed when the electric current flows orthogonal to the direction of the in-plane compositional gradient due to the in-plane symmetry breaking. This work proves that the MPG is a good candidate to be utilized in high-density and efficient magnetoresistive random access memory devices and other spintronic applications.
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Affiliation(s)
- Lizhu Ren
- Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore
| | - Chenghang Zhou
- Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore
| | - Xiaohe Song
- Integrative Sciences and Engineering Programme, NUS Graduate School, National University of Singapore, 119077, Singapore
- Department of Physics, National University of Singapore, 117551 Singapore
| | - Herng Tun Seng
- Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore
| | - Liang Liu
- Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Chaojiang Li
- School of Mechanical and Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Tieyang Zhao
- Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore
| | - Zhenyi Zheng
- Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore
| | - Jun Ding
- Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore
| | - Yuan Ping Feng
- Department of Physics, National University of Singapore, 117551 Singapore
| | - Jingsheng Chen
- Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore
| | - Kie Leong Teo
- Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore
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9
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Ham WS, Ho TH, Shiota Y, Iino T, Ando F, Ikebuchi T, Kotani Y, Nakamura T, Kan D, Shimakawa Y, Moriyma T, Im E, Lee N, Kim K, Hong SC, Rhim SH, Ono T, Kim S. Bulk Rashba-Type Spin Splitting in Non-Centrosymmetric Artificial Superlattices. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2206800. [PMID: 36808490 PMCID: PMC10131871 DOI: 10.1002/advs.202206800] [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: 11/19/2022] [Revised: 01/25/2023] [Indexed: 06/18/2023]
Abstract
Spin current, converted from charge current via spin Hall or Rashba effects, can transfer its angular momentum to local moments in a ferromagnetic layer. In this regard, the high charge-to-spin conversion efficiency is required for magnetization manipulation for developing future memory or logic devices including magnetic random-access memory. Here, the bulk Rashba-type charge-to-spin conversion is demonstrated in an artificial superlattice without centrosymmetry. The charge-to-spin conversion in [Pt/Co/W] superlattice with sub-nm scale thickness shows strong W thickness dependence. When the W thickness becomes 0.6 nm, the observed field-like torque efficiency is about 0.6, which is an order larger than other metallic heterostructures. First-principles calculation suggests that such large field-like torque arises from bulk-type Rashba effect due to the vertically broken inversion symmetry inherent from W layers. The result implies that the spin splitting in a band of such an ABC-type artificial SL can be an additional degree of freedom for the large charge-to-spin conversion.
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Affiliation(s)
- Woo Seung Ham
- Institute for Chemical ResearchKyoto UniversityUjiKyoto611‐0011Japan
| | - Thi Huynh Ho
- Department of PhysicsUniversity of UlsanUlsan44610Korea
| | - Yoichi Shiota
- Institute for Chemical ResearchKyoto UniversityUjiKyoto611‐0011Japan
| | - Tatsuya Iino
- Institute for Chemical ResearchKyoto UniversityUjiKyoto611‐0011Japan
| | - Fuyuki Ando
- Institute for Chemical ResearchKyoto UniversityUjiKyoto611‐0011Japan
| | - Tetsuya Ikebuchi
- Institute for Chemical ResearchKyoto UniversityUjiKyoto611‐0011Japan
| | - Yoshinori Kotani
- Japan Synchrotron Radiation Research Institute (JASRI)SayoHyogo679‐5198Japan
| | - Tetsuya Nakamura
- Japan Synchrotron Radiation Research Institute (JASRI)SayoHyogo679‐5198Japan
- International Center for Synchrotron Radiation Innovation SmartTohoku UniversitySendai980‐8572Japan
| | - Daisuke Kan
- Institute for Chemical ResearchKyoto UniversityUjiKyoto611‐0011Japan
| | - Yuichi Shimakawa
- Institute for Chemical ResearchKyoto UniversityUjiKyoto611‐0011Japan
| | - Takahiro Moriyma
- Institute for Chemical ResearchKyoto UniversityUjiKyoto611‐0011Japan
| | - Eunji Im
- Department of PhysicsUniversity of UlsanUlsan44610Korea
| | - Nyun‐Jong Lee
- Department of PhysicsUniversity of UlsanUlsan44610Korea
| | - Kyoung‐Whan Kim
- Center for SpintronicsKorea Institute of Science and Technology (KIST)Seoul02792Korea
| | | | - Sonny H. Rhim
- Department of PhysicsUniversity of UlsanUlsan44610Korea
| | - Teruo Ono
- Institute for Chemical ResearchKyoto UniversityUjiKyoto611‐0011Japan
| | - Sanghoon Kim
- Department of PhysicsUniversity of UlsanUlsan44610Korea
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Zhu L, Ralph DC. Strong variation of spin-orbit torques with relative spin relaxation rates in ferrimagnets. Nat Commun 2023; 14:1778. [PMID: 36997579 PMCID: PMC10063689 DOI: 10.1038/s41467-023-37506-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 03/20/2023] [Indexed: 04/03/2023] Open
Abstract
Spin-orbit torques (SOTs) have been widely understood as an interfacial transfer of spin that is independent of the bulk properties of the magnetic layer. Here, we report that SOTs acting on ferrimagnetic FexTb1-x layers decrease and vanish upon approaching the magnetic compensation point because the rate of spin transfer to the magnetization becomes much slower than the rate of spin relaxation into the crystal lattice due to spin-orbit scattering. These results indicate that the relative rates of competing spin relaxation processes within magnetic layers play a critical role in determining the strength of SOTs, which provides a unified understanding for the diverse and even seemingly puzzling SOT phenomena in ferromagnetic and compensated systems. Our work indicates that spin-orbit scattering within the magnet should be minimized for efficient SOT devices. We also find that the interfacial spin-mixing conductance of interfaces of ferrimagnetic alloys (such as FexTb1-x) is as large as that of 3d ferromagnets and insensitive to the degree of magnetic compensation.
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Affiliation(s)
- Lijun Zhu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China.
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Daniel C Ralph
- Cornell University, Ithaca, NY, 14850, USA
- Kavli Institute at Cornell, Ithaca, NY, 14850, USA
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11
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Rout PC, Schwingenschlögl U. Large Spin Coherence Length and High Photovoltaic Efficiency of the Room Temperature Ferrimagnet Ca 2 FeOsO 6 by Strain Engineering. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2106037. [PMID: 35863902 PMCID: PMC9475547 DOI: 10.1002/advs.202106037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 06/13/2022] [Indexed: 06/15/2023]
Abstract
The influence of epitaxial strain on the electronic, magnetic, and optical properties of the distorted double perovskite Ca2 FeOsO6 is studied. These calculations show that the compound realizes a monoclinic structure with P21 /n space group from -6% to +6% strain. While it retains ferrimagnetic ordering with a net magnetic moment of 2 μB per formula unit at low strain, it undergoes transitions into E-antiferromagnetic and C-antiferromagnetic phases at -5% and +5% strain, respectively. It is shown that spin frustration reduces the critical temperature of the ferrimagnetic ordering from the mean field value of 600-350 K, in excellent agreement with the experimental value of 320 K. It is also shown that the critical temperature can be tuned efficiently through strain and that the spin coherence length surpasses that of Sr2 FeMoO6 under tensile strain. An indirect-to-direct bandgap transition is observed at +5% strain. Localization of the valence and conduction states on different transition metal sublattices enables efficient electron-hole separation upon photoexcitation. The calculated spectroscopic limited maximum efficiency of up to 33% points to excellent potential of Ca2 FeOsO6 in solar cell applications.
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Affiliation(s)
- Paresh C. Rout
- Physical Sciences and Engineering Division (PSE)King Abdullah University of Science and Technology (KAUST)Thuwal23955‐6900Saudi Arabia
| | - Udo Schwingenschlögl
- Physical Sciences and Engineering Division (PSE)King Abdullah University of Science and Technology (KAUST)Thuwal23955‐6900Saudi Arabia
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12
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Pal B, Hazra BK, Göbel B, Jeon JC, Pandeya AK, Chakraborty A, Busch O, Srivastava AK, Deniz H, Taylor JM, Meyerheim H, Mertig I, Yang SH, Parkin SSP. Setting of the magnetic structure of chiral kagome antiferromagnets by a seeded spin-orbit torque. SCIENCE ADVANCES 2022; 8:eabo5930. [PMID: 35704587 PMCID: PMC9200275 DOI: 10.1126/sciadv.abo5930] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 04/29/2022] [Indexed: 06/03/2023]
Abstract
The current-induced spin-orbit torque switching of ferromagnets has had huge impact in spintronics. However, short spin-diffusion lengths limit the thickness of switchable ferromagnetic layers, thereby limiting their thermal stability. Here, we report a previously unobserved seeded spin-orbit torque (SSOT) by which current can set the magnetic states of even thick layers of the chiral kagome antiferromagnet Mn3Sn. The mechanism involves setting the orientation of the antiferromagnetic domains in a thin region at the interface with spin currents arising from an adjacent heavy metal while also heating the layer above its magnetic ordering temperature. This interface region seeds the resulting spin texture of the entire layer as it cools down and, thereby, overcomes the thickness limitation of conventional spin-orbit torques. SSOT switching in Mn3Sn can be extended beyond chiral antiferromagnets to diverse magnetic systems and provides a path toward the development of highly efficient, high-speed, and thermally stable spintronic devices.
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Affiliation(s)
- Banabir Pal
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Binoy K. Hazra
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Börge Göbel
- Institute of Physics, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Jae-Chun Jeon
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Avanindra K. Pandeya
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Anirban Chakraborty
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Oliver Busch
- Institute of Physics, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Abhay K. Srivastava
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Hakan Deniz
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - James M. Taylor
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Holger Meyerheim
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Ingrid Mertig
- Institute of Physics, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - See-Hun Yang
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
| | - Stuart S. P. Parkin
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
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13
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Singh S, Basha MA, Bhatt H, Kumar Y, Gupta M. Interface morphology driven exchange interaction and magnetization reversal in a Gd/Co multilayer. Phys Chem Chem Phys 2022; 24:6580-6589. [PMID: 35234230 DOI: 10.1039/d1cp05711a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rare-earth (RE)/transition metal (TM) ferromagnetic heterostructures with competing interfacial coupling and Zeeman energy provide a rich ground to study different phase states as a function of magnetic field and temperature. The interface morphology as a knob in these RE/TM heterostructures provides an excellent opportunity to engineer the macroscopic magnetic response by tuning the interface dependent microscopic interactions between the layers. We have investigated the interface morphology driven structure and magnetic properties of a Gd/Co multilayer. The interface morphology of the multilayer was controlled by annealing the multilayer at a relatively low temperature of 573 K under vacuum conditions. Combining the different experimental techniques and a simple one-dimensional spin-based model calculation, we studied the detailed magnetic structure and magnetization reversal mechanism in this system across compensation temperature (Tcomp), which suggested a strong interface dependent coupling in the system. We showed that changes in the interface morphology of the Gd/Co multilayer strongly influence the macroscopic magnetic properties of the system. The calculation also confirms the formation of a helical magnetic structure with a 2π domain wall in this system below Tcomp. The experimental finding and the simulation of this technologically important system will help to understand the physics of all-optical switching and related applications.
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Affiliation(s)
- Surendra Singh
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India. .,Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - M A Basha
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India. .,Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Harsh Bhatt
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India. .,Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Yogesh Kumar
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
| | - M Gupta
- UGC DAE CSR, University Campus, Khandwa Road, Indore 452017, India
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14
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Kim SK, Beach GSD, Lee KJ, Ono T, Rasing T, Yang H. Ferrimagnetic spintronics. NATURE MATERIALS 2022; 21:24-34. [PMID: 34949868 DOI: 10.1038/s41563-021-01139-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 09/21/2021] [Indexed: 06/14/2023]
Abstract
Ferrimagnets composed of multiple and antiferromagnetically coupled magnetic elements have attracted much attention recently as a material platform for spintronics. They offer the combined advantages of both ferromagnets and antiferromagnets, namely the easy control and detection of their net magnetization by an external field, antiferromagnetic-like dynamics faster than ferromagnetic dynamics and the potential for high-density devices. This Review summarizes recent progress in ferrimagnetic spintronics, with particular attention to the most-promising functionalities of ferrimagnets, which include their spin transport, spin texture dynamics and all-optical switching.
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Affiliation(s)
- Se Kwon Kim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Geoffrey S D Beach
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kyung-Jin Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.
- Department of Materials Science and Engineering, Korea University, Seoul, Korea.
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Korea.
| | - Teruo Ono
- Institute of Chemical Research, Kyoto University, Kyoto, Japan
- Center for Spintronics Research Network (CSRN), Graduate School of Engineering Science, Osaka University, Osaka, Japan
| | - Theo Rasing
- Institute for Molecules and Materials, Radboud University, Nijmegen, the Netherlands
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, China
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
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15
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Takeuchi Y, Yamane Y, Yoon JY, Itoh R, Jinnai B, Kanai S, Ieda J, Fukami S, Ohno H. Chiral-spin rotation of non-collinear antiferromagnet by spin-orbit torque. NATURE MATERIALS 2021; 20:1364-1370. [PMID: 33986515 DOI: 10.1038/s41563-021-01005-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
Electrical manipulation of magnetic materials by current-induced spin torque constitutes the basis of spintronics. Here, we show an unconventional response to spin-orbit torque of a non-collinear antiferromagnet Mn3Sn, which has attracted attention owing to its large anomalous Hall effect despite a vanishingly small net magnetization. In epitaxial heavy-metal/Mn3Sn heterostructures, we observe a characteristic fluctuation of the Hall resistance under the application of electric current. This observation is explained by a rotation of the chiral-spin structure of Mn3Sn driven by spin-orbit torque. We find that the variation of the magnitude of anomalous Hall effect fluctuation with sample size correlates with the number of magnetic domains in the Mn3Sn layer. In addition, the dependence of the critical current on Mn3Sn layer thickness reveals that spin-orbit torque generated by small current densities, below 20 MA cm-2, effectively acts on the chiral-spin structure even in Mn3Sn layers that are thicker than 20 nm. The results provide additional pathways for electrical manipulation of magnetic materials.
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Affiliation(s)
- Yutaro Takeuchi
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba-ku, Sendai, Japan.
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan.
| | - Yuta Yamane
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba-ku, Sendai, Japan.
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan.
| | - Ju-Young Yoon
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba-ku, Sendai, Japan
| | - Ryuichi Itoh
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba-ku, Sendai, Japan
| | - Butsurin Jinnai
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
| | - Shun Kanai
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba-ku, Sendai, Japan
- Center for Spintronics Research Network, Tohoku University, Sendai, Japan
- Division for the Establishment of Frontier Sciences, Tohoku University, Sendai, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, Sendai, Japan
| | - Jun'ichi Ieda
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba-ku, Sendai, Japan
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Japan
| | - Shunsuke Fukami
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba-ku, Sendai, Japan.
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan.
- Center for Spintronics Research Network, Tohoku University, Sendai, Japan.
- Center for Science and Innovation in Spintronics, Tohoku University, Sendai, Japan.
- Center for Innovative Integrated Electronic Systems, Tohoku University, Sendai, Japan.
| | - Hideo Ohno
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba-ku, Sendai, Japan
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
- Center for Spintronics Research Network, Tohoku University, Sendai, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, Sendai, Japan
- Center for Innovative Integrated Electronic Systems, Tohoku University, Sendai, Japan
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16
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Ren L, Liu L, Shu X, Lin W, Yang P, Chen J, Teo KL. Spin-Orbit Torque Switching of a High-Quality Perpendicularly Magnetized Ferrimagnetic Heusler Mn 3Ge Film. ACS APPLIED MATERIALS & INTERFACES 2021; 13:18294-18300. [PMID: 33822573 DOI: 10.1021/acsami.1c01720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Current-induced spin-orbit torque (SOT) switching of magnetization has attracted great interest due to its potential application in magnetic memory devices, which offer low-energy consumption and high-speed writing. However, most of the SOT studies on perpendicularly magnetized anisotropy (PMA) magnets have been limited to heterostructures with interfacial PMA and poor thermal stability. Here, we experimentally demonstrate a SOT magnetization switching for a ferrimagnetic D022-Mn3Ge film with high bulk PMA and robust thermal stability factor under a critical current density of 6.6 × 1011 A m-2 through the spin Hall effect of an adjacent capping Pt and a buffer Cr layer. A large effective damping-like SOT efficiency of 2.37 mT/1010 A m-2 is determined using harmonic measurements in the structure. The effect of the double-spin source layers and the negative-exchange interaction of the ferrimagnet may explain the large SOT efficiency and the manifested magnetization switching of Mn3Ge. Our findings demonstrate that D022-Mn3Ge is a promising candidate for application in high-density SOT magnetic random-access memory devices.
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Affiliation(s)
- Lizhu Ren
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Liang Liu
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Xinyu Shu
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Weinan Lin
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Ping Yang
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 117603, Singapore
| | - Jingsheng Chen
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
| | - Kie Leong Teo
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
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17
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Zhang K, Han S, Lee Y, Coak MJ, Kim J, Hwang I, Son S, Shin J, Lim M, Jo D, Kim K, Kim D, Lee HW, Park JG. Gigantic Current Control of Coercive Field and Magnetic Memory Based on Nanometer-Thin Ferromagnetic van der Waals Fe 3 GeTe 2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2004110. [PMID: 33283320 DOI: 10.1002/adma.202004110] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/25/2020] [Indexed: 06/12/2023]
Abstract
Controlling magnetic states by a small current is essential for the next-generation of energy-efficient spintronic devices. However, it invariably requires considerable energy to change a magnetic ground state of intrinsically quantum nature governed by fundamental Hamiltonian, once stabilized below a phase-transition temperature. Here, it is reported that, surprisingly, an in-plane current can tune the magnetic state of the nanometer-thin van der Waals ferromagnet Fe3 GeTe2 from a hard magnetic state to a soft magnetic state. It is a direct demonstration of the current-induced substantial reduction of the coercive field. This surprising finding is possible because the in-plane current produces a highly unusual type of gigantic spin-orbit torque for Fe3 GeTe2 . In addition, a working model of a new nonvolatile magnetic memory based on the principle of the discovery in Fe3 GeTe2 , controlled by a tiny current, is further demonstrated. The findings open up a new window of exciting opportunities for magnetic van der Waals materials with potentially huge impact on the future development of spintronic and magnetic memory.
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Affiliation(s)
- Kaixuan Zhang
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, 08826, South Korea
- Center for Quantum Materials, Seoul National University, Seoul, 08826, South Korea
| | - Seungyun Han
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, South Korea
| | - Youjin Lee
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, 08826, South Korea
- Center for Quantum Materials, Seoul National University, Seoul, 08826, South Korea
| | - Matthew J Coak
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, 08826, South Korea
| | - Junghyun Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, 08826, South Korea
- Center for Quantum Materials, Seoul National University, Seoul, 08826, South Korea
| | - Inho Hwang
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, 08826, South Korea
- Center for Quantum Materials, Seoul National University, Seoul, 08826, South Korea
| | - Suhan Son
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, 08826, South Korea
- Center for Quantum Materials, Seoul National University, Seoul, 08826, South Korea
| | - Jeacheol Shin
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, 08826, South Korea
| | - Mijin Lim
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, South Korea
| | - Daegeun Jo
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, South Korea
| | - Kyoo Kim
- Korea Atomic Energy Research Institute, 111 Daedeok-daero, Daejeon, 34057, South Korea
| | - Dohun Kim
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, 08826, South Korea
| | - Hyun-Woo Lee
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, South Korea
- Asia Pacific Center for Theoretical Physics, 77 Cheongam-ro, Nam-gu, Pohang, 3773, South Korea
| | - Je-Geun Park
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, 08826, South Korea
- Center for Quantum Materials, Seoul National University, Seoul, 08826, South Korea
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Abstract
Science, engineering, and medicine ultimately demand fast information processing with ultra-low power consumption. The recently developed spin-orbit torque (SOT)-induced magnetization switching paradigm has been fueling opportunities for spin-orbitronic devices, i.e., enabling SOT memory and logic devices at sub-nano second and sub-picojoule regimes. Importantly, spin-orbitronic devices are intrinsic of nonvolatility, anti-radiation, unlimited endurance, excellent stability, and CMOS compatibility, toward emerging applications, e.g., processing in-memory, neuromorphic computing, probabilistic computing, and 3D magnetic random access memory. Nevertheless, the cutting-edge SOT-based devices and application remain at a premature stage owing to the lack of scalable methodology on the field-free SOT switching. Moreover, spin-orbitronics poises as an interdisciplinary field to be driven by goals of both fundamental discoveries and application innovations, to open fascinating new paths for basic research and new line of technologies. In this perspective, the specific challenges and opportunities are summarized to exert momentum on both research and eventual applications of spin-orbitronic devices.
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Affiliation(s)
- Yi Cao
- Beijing Academy of Quantum Information Sciences, Beijing 100193, P. R. China
| | - Guozhong Xing
- Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, P. R. China
| | - Huai Lin
- Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, P. R. China
| | - Nan Zhang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, P. R. China
| | - Houzhi Zheng
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, P. R. China
| | - Kaiyou Wang
- Beijing Academy of Quantum Information Sciences, Beijing 100193, P. R. China
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, P. R. China
- Corresponding author
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19
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Ryu J, Lee S, Lee KJ, Park BG. Current-Induced Spin-Orbit Torques for Spintronic Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1907148. [PMID: 32141681 DOI: 10.1002/adma.201907148] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/13/2019] [Indexed: 06/10/2023]
Abstract
Control of magnetization in magnetic nanostructures is essential for development of spintronic devices because it governs fundamental device characteristics such as energy consumption, areal density, and operation speed. In this respect, spin-orbit torque (SOT), which originates from the spin-orbit interaction, has been widely investigated due to its efficient manipulation of the magnetization using in-plane current. SOT spearheads novel spintronic applications including high-speed magnetic memories, reconfigurable logics, and neuromorphic computing. Herein, recent advances in SOT research, highlighting the considerable benefits and challenges of SOT-based spintronic devices, are reviewed. First, the materials and structural engineering that enhances SOT efficiency are discussed. Then major experimental results for field-free SOT switching of perpendicular magnetization are summarized, which includes the introduction of an internal effective magnetic field and the generation of a distinct spin current with out-of-plane spin polarization. Finally, advanced SOT functionalities are presented, focusing on the demonstration of reconfigurable and complementary operation in spin logic devices.
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Affiliation(s)
- Jeongchun Ryu
- Department of Materials Science and Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Soogil Lee
- Department of Materials Science and Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Kyung-Jin Lee
- Department of Materials Science and Engineering and KU-KIST Graduate School of Converging Science and Technology, Korea University, 145 Anam-ro, Anam-dong, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Byong-Guk Park
- Department of Materials Science and Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
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20
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Liu L, Zhao X, Liu W, Song Y, Zhao X, Zhang Z. Influence of rare earth metal Ho on the interfacial Dzyaloshinskii-Moriya interaction and spin torque efficiency in Pt/Co/Ho multilayers. NANOSCALE 2020; 12:12444-12453. [PMID: 32495785 DOI: 10.1039/d0nr02168g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Owing to the large spin-orbit coupling and tunable magnetization, heavy rare-earth metals Gd and Tb have great effects on the enhancement of spin-orbit torque (SOT) and fast domain wall (DW) motion. However, the reports on the heavy rare-earth metal Ho with more 4f electrons in the research of spintronics are limited. In this work, we found that the interfacial Dzyaloshinskii-Moriya interaction (DMI) and SOT in Pt/Co/Ho multilayers can be strongly influenced by changing the thickness of the Ho (tHo) layer. At tHo = 2.4 nm, DMI exchange constant |D| and spin torque efficiency ξDL reach maximum values of 1.24 mJ m-2 and 0.137 respectively, which are comparable with those in other Pt/Co/nonmagnetic (NM) layer structures. Deterministic current-induced magnetization switching with a low critical current density of 106 A cm-2 can be realized when tHo is less than 5 nm. The Néel-type DW with left-handed chirality and positive sign D can be determined by observing the current-induced asymmetric DW motion. Our results are helpful to prompt the application of heavy rare-earth elements in the fields of the DMI, SOT and chiral DW dynamics.
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Affiliation(s)
- Long Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China. and School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Xiaotian Zhao
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
| | - Wei Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
| | - Yuhang Song
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China. and School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Xinguo Zhao
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
| | - Zhidong Zhang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
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21
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Avilés-Félix L, Olivier A, Li G, Davies CS, Álvaro-Gómez L, Rubio-Roy M, Auffret S, Kirilyuk A, Kimel AV, Rasing T, Buda-Prejbeanu LD, Sousa RC, Dieny B, Prejbeanu IL. Single-shot all-optical switching of magnetization in Tb/Co multilayer-based electrodes. Sci Rep 2020; 10:5211. [PMID: 32251329 PMCID: PMC7089968 DOI: 10.1038/s41598-020-62104-w] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 03/06/2020] [Indexed: 11/10/2022] Open
Abstract
Ever since the first observation of all-optical switching of magnetization in the ferrimagnetic alloy GdFeCo using femtosecond laser pulses, there has been significant interest in exploiting this process for data-recording applications. In particular, the ultrafast speed of the magnetic reversal can enable the writing speeds associated with magnetic memory devices to be potentially pushed towards THz frequencies. This work reports the development of perpendicular magnetic tunnel junctions incorporating a stack of Tb/Co nanolayers whose magnetization can be all-optically controlled via helicity-independent single-shot switching. Toggling of the magnetization of the Tb/Co electrode was achieved using either 60 femtosecond-long or 5 picosecond-long laser pulses, with incident fluences down to 3.5 mJ/cm2, for Co-rich compositions of the stack either in isolation or coupled to a CoFeB-electrode/MgO-barrier tunnel-junction stack. Successful switching of the CoFeB-[Tb/Co] electrodes was obtained even after annealing at 250 °C. After integration of the [Tb/Co]-based electrodes within perpendicular magnetic tunnel junctions yielded a maximum tunneling magnetoresistance signal of 41% and RxA value of 150 Ωμm2 with current-in-plane measurements and ratios between 28% and 38% in nanopatterned pillars. These results represent a breakthrough for the development of perpendicular magnetic tunnel junctions controllable using single laser pulses, and offer a technologically-viable path towards the realization of hybrid spintronic-photonic systems featuring THz switching speeds.
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Affiliation(s)
- L Avilés-Félix
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France.
| | - A Olivier
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - G Li
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525, AJ Nijmegen, The Netherlands
| | - C S Davies
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525, AJ Nijmegen, The Netherlands
- FELIX Laboratory, Radboud University, 7 Toernooiveld, 6525, ED Nijmegen, The Netherlands
| | - L Álvaro-Gómez
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - M Rubio-Roy
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - S Auffret
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - A Kirilyuk
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525, AJ Nijmegen, The Netherlands
- FELIX Laboratory, Radboud University, 7 Toernooiveld, 6525, ED Nijmegen, The Netherlands
| | - A V Kimel
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525, AJ Nijmegen, The Netherlands
| | - Th Rasing
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525, AJ Nijmegen, The Netherlands
| | - L D Buda-Prejbeanu
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - R C Sousa
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - B Dieny
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - I L Prejbeanu
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
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