1
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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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2
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Kang J, Han D, Lee K, Ko S, Koh D, Park C, Ahn J, Yu M, Pakala M, Noh S, Lee H, Kwon J, Kim KJ, Park J, Lee S, Lee J, Park BG. Highly Reliable Magnetic Memory-Based Physical Unclonable Functions. ACS NANO 2024; 18:12853-12860. [PMID: 38718347 PMCID: PMC11112974 DOI: 10.1021/acsnano.4c00078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 04/12/2024] [Accepted: 04/25/2024] [Indexed: 05/22/2024]
Abstract
Magnetic random-access memory (MRAM), which stores information through control of the magnetization direction, offers promising features as a viable nonvolatile memory alternative, including high endurance and successful large-scale commercialization. Recently, MRAM applications have extended beyond traditional memories, finding utility in emerging computing architectures such as in-memory computing and probabilistic bits. In this work, we report highly reliable MRAM-based security devices, known as physical unclonable functions (PUFs), achieved by exploiting nanoscale perpendicular magnetic tunnel junctions (MTJs). By intentionally randomizing the magnetization direction of the antiferromagnetically coupled reference layer of the MTJs, we successfully create an MRAM-PUF. The proposed PUF shows ideal uniformity and uniqueness and, in particular, maintains performance over a wide temperature range from -40 to +150 °C. Moreover, rigorous testing with more than 1584 challenge-response pairs of 64 bits each confirms resilience against machine learning attacks. These results, combined with the merits of commercialized MRAM technology, would facilitate the implementation of MRAM-PUFs.
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Affiliation(s)
- Jaimin Kang
- Department
of Material Science and Engineering, Korea
Advanced Institute of Science and Technology (KAIST), 291 Daehak-road, Yuseong-gu, Daejeon 34141, Korea
| | - Donghyeon Han
- Department
of Material Science and Engineering, Korea
Advanced Institute of Science and Technology (KAIST), 291 Daehak-road, Yuseong-gu, Daejeon 34141, Korea
| | - Kyungchul Lee
- Department
of Electrical Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea
| | - San Ko
- Department
of Physics, Korea Advanced Institute of
Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Daekyu Koh
- Department
of Material Science and Engineering, Korea
Advanced Institute of Science and Technology (KAIST), 291 Daehak-road, Yuseong-gu, Daejeon 34141, Korea
| | - Chando Park
- Applied
Materials, Inc., 3050 Bowers Avenue, Santa Clara, California 95054, United States
| | - Jaesoo Ahn
- Applied
Materials, Inc., 3050 Bowers Avenue, Santa Clara, California 95054, United States
| | - Minrui Yu
- Applied
Materials, Inc., 3050 Bowers Avenue, Santa Clara, California 95054, United States
| | - Mahendra Pakala
- Applied
Materials, Inc., 3050 Bowers Avenue, Santa Clara, California 95054, United States
| | - Sujung Noh
- R&D
Division, Hyundai Motor Company, 150 Hyundaiyeonguso-ro, Namyang-eup, Hwaseong 18280, Korea
| | - Hansaem Lee
- R&D
Division, Hyundai Motor Company, 150 Hyundaiyeonguso-ro, Namyang-eup, Hwaseong 18280, Korea
| | - JoonHyun Kwon
- R&D
Division, Hyundai Motor Company, 150 Hyundaiyeonguso-ro, Namyang-eup, Hwaseong 18280, Korea
| | - Kab-Jin Kim
- Department
of Physics, Korea Advanced Institute of
Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Jongsun Park
- Department
of Electrical Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea
| | - Soogil Lee
- Department
of Material Science and Engineering, Korea
Advanced Institute of Science and Technology (KAIST), 291 Daehak-road, Yuseong-gu, Daejeon 34141, Korea
- Department
of Electronic Engineering, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam 13120, Korea
| | - Jisung Lee
- R&D
Division, Hyundai Motor Company, 150 Hyundaiyeonguso-ro, Namyang-eup, Hwaseong 18280, Korea
| | - Byong-Guk Park
- Department
of Material Science and Engineering, Korea
Advanced Institute of Science and Technology (KAIST), 291 Daehak-road, Yuseong-gu, Daejeon 34141, Korea
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3
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Fu Z, Samarawickrama PI, Ackerman J, Zhu Y, Mao Z, Watanabe K, Taniguchi T, Wang W, Dahnovsky Y, Wu M, Chien T, Tang J, MacDonald AH, Chen H, Tian J. Tunneling current-controlled spin states in few-layer van der Waals magnets. Nat Commun 2024; 15:3630. [PMID: 38693113 PMCID: PMC11063166 DOI: 10.1038/s41467-024-47820-5] [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: 07/19/2023] [Accepted: 04/12/2024] [Indexed: 05/03/2024] Open
Abstract
Effective control of magnetic phases in two-dimensional magnets would constitute crucial progress in spintronics, holding great potential for future computing technologies. Here, we report a new approach of leveraging tunneling current as a tool for controlling spin states in CrI3. We reveal that a tunneling current can deterministically switch between spin-parallel and spin-antiparallel states in few-layer CrI3, depending on the polarity and amplitude of the current. We propose a mechanism involving nonequilibrium spin accumulation in the graphene electrodes in contact with the CrI3 layers. We further demonstrate tunneling current-tunable stochastic switching between multiple spin states of the CrI3 tunnel devices, which goes beyond conventional bi-stable stochastic magnetic tunnel junctions and has not been documented in two-dimensional magnets. Our findings not only address the existing knowledge gap concerning the influence of tunneling currents in controlling the magnetism in two-dimensional magnets, but also unlock possibilities for energy-efficient probabilistic and neuromorphic computing.
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Affiliation(s)
- ZhuangEn Fu
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY, 82071, USA
- Center for Quantum Information Science and Engineering, University of Wyoming, Laramie, WY, 82071, USA
| | - Piumi I Samarawickrama
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY, 82071, USA
- Center for Quantum Information Science and Engineering, University of Wyoming, Laramie, WY, 82071, USA
| | - John Ackerman
- Department of Chemical Biomedical Engineering, University of Wyoming, Laramie, WY, 82071, USA
| | - Yanglin Zhu
- Department of Physics, The Pennsylvania State University, University Park, PA, 16801, USA
| | - Zhiqiang Mao
- Department of Physics, The Pennsylvania State University, University Park, PA, 16801, USA
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Wenyong Wang
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY, 82071, USA
- Center for Quantum Information Science and Engineering, University of Wyoming, Laramie, WY, 82071, USA
| | - Yuri Dahnovsky
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY, 82071, USA
- Center for Quantum Information Science and Engineering, University of Wyoming, Laramie, WY, 82071, USA
| | - Mingzhong Wu
- Department of Physics and Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, 02115, USA
| | - TeYu Chien
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY, 82071, USA
- Center for Quantum Information Science and Engineering, University of Wyoming, Laramie, WY, 82071, USA
| | - Jinke Tang
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY, 82071, USA
- Center for Quantum Information Science and Engineering, University of Wyoming, Laramie, WY, 82071, USA
| | - Allan H MacDonald
- Department of Physics, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Hua Chen
- Department of Physics and School of Advanced Materials Discovery, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Jifa Tian
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY, 82071, USA.
- Center for Quantum Information Science and Engineering, University of Wyoming, Laramie, WY, 82071, USA.
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4
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Wang W, Liu J, Su W, Han Y, Du Q, Wu J, Hu Z, Wang C, Jiang Z, Wang Z, Liu M. Heat-Assisted Magnetization Switching in Flexible Spin-Orbit Torque Devices. NANO LETTERS 2024; 24:2003-2010. [PMID: 38306120 DOI: 10.1021/acs.nanolett.3c04535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Heat-assisted magnetic anisotropy engineering has been successfully used in selective magnetic writing and microwave amplification due to a large interfacial thermal resistance between the MgO barrier and the adjacent ferromagnetic layers. However, in spin-orbit torque devices, the writing current does not flow through the tunnel barrier, resulting in a negligible heating effect due to efficient heat dissipation. Here, we report a dramatically reduced switching current density of ∼2.59 MA/cm2 in flexible spin-orbit torque heterostructures, indicating a 98% decrease in writing energy consumption compared with that on a silicon substrate. The reduced driving current density is enabled by the dramatically decreased magnetic anisotropy due to Joule dissipation and the lower thermal conductivity of the flexible substrate. The large magnetic anisotropy could be fully recovered after the impulse, indicating retained high stability. These results pave the way for flexible spintronics with the otherwise incompatible advantages of low power consumption and high stability.
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Affiliation(s)
- Wenli Wang
- State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Engineering Research Center of Spin Quantum Sensor Chips, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jiaqiang Liu
- State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Engineering Research Center of Spin Quantum Sensor Chips, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Wei Su
- State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Engineering Research Center of Spin Quantum Sensor Chips, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Yongliang Han
- State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Engineering Research Center of Spin Quantum Sensor Chips, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Qin Du
- State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Engineering Research Center of Spin Quantum Sensor Chips, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jingen Wu
- State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Engineering Research Center of Spin Quantum Sensor Chips, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Zhongqiang Hu
- State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Engineering Research Center of Spin Quantum Sensor Chips, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Chenying Wang
- State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Engineering Research Center of Spin Quantum Sensor Chips, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Zhuangde Jiang
- State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Engineering Research Center of Spin Quantum Sensor Chips, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Zhiguang Wang
- State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Engineering Research Center of Spin Quantum Sensor Chips, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Ming Liu
- State Key Laboratory for Manufacturing Systems Engineering, Electronic Materials Research Laboratory, Engineering Research Center of Spin Quantum Sensor Chips, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
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5
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Xu M, Chen X, Guo Y, Wang Y, Qiu D, Du X, Cui Y, Wang X, Xiong J. Reconfigurable Neuromorphic Computing: Materials, Devices, and Integration. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2301063. [PMID: 37285592 DOI: 10.1002/adma.202301063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/15/2023] [Indexed: 06/09/2023]
Abstract
Neuromorphic computing has been attracting ever-increasing attention due to superior energy efficiency, with great promise to promote the next wave of artificial general intelligence in the post-Moore era. Current approaches are, however, broadly designed for stationary and unitary assignments, thus encountering reluctant interconnections, power consumption, and data-intensive computing in that domain. Reconfigurable neuromorphic computing, an on-demand paradigm inspired by the inherent programmability of brain, can maximally reallocate finite resources to perform the proliferation of reproducibly brain-inspired functions, highlighting a disruptive framework for bridging the gap between different primitives. Although relevant research has flourished in diverse materials and devices with novel mechanisms and architectures, a precise overview remains blank and urgently desirable. Herein, the recent strides along this pursuit are systematically reviewed from material, device, and integration perspectives. At the material and device level, one comprehensively conclude the dominant mechanisms for reconfigurability, categorized into ion migration, carrier migration, phase transition, spintronics, and photonics. Integration-level developments for reconfigurable neuromorphic computing are also exhibited. Finally, a perspective on the future challenges for reconfigurable neuromorphic computing is discussed, definitely expanding its horizon for scientific communities.
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Affiliation(s)
- Minyi Xu
- State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Xinrui Chen
- State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Yehao Guo
- State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Yang Wang
- State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Dong Qiu
- State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Xinchuan Du
- State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Yi Cui
- State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Xianfu Wang
- State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Jie Xiong
- State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
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6
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Huang Q, Liu S, Yang T, Xie R, Cai L, Cao Q, Lü W, Bai L, Tian Y, Yan S. Current-Induced Magnetization Switching in Light-Metal-Oxide/Ferromagnetic-Metal Bilayers via Orbital Rashba Effect. NANO LETTERS 2023. [PMID: 38019659 DOI: 10.1021/acs.nanolett.3c03972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
The orbital angular momentum (OAM) generation as well as its associated orbital torque is currently a matter of great interest in spin-orbitronics and is receiving increasing attention. In particular, recent theoretical work predicts that the oxidized light metal Cu can serve as an efficient OAM generator through its surface orbital Rashba effect. Here, for the first time, the crucial current-induced magnetic-field-free in-plane magnetization reversal is experimentally demonstrated in CoFeB/CuOx bilayers without any heavy elements. We show that the critical current density can be comparable to that of strong spin-orbit coupling systems with heavy metals (Pt and Ta) and that the magnetization reversal mechanism is governed by coherent rotation in the grains through the second-harmonic and magneto-optical Kerr effect measurements. Our results indicate that light metal oxides can play an equally important role as heavy metals in magnetization reversal, broadening the choice of materials for engineering spintronic devices.
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Affiliation(s)
- QiKun Huang
- Spintronics Institute, University of Jinan, Jinan 250022, China
| | - Senmiao Liu
- Spintronics Institute, University of Jinan, Jinan 250022, China
| | - Tianxiang Yang
- Spintronics Institute, University of Jinan, Jinan 250022, China
| | - Ronghuan Xie
- Spintronics Institute, University of Jinan, Jinan 250022, China
| | - Li Cai
- Spintronics Institute, University of Jinan, Jinan 250022, China
| | - Qiang Cao
- Spintronics Institute, University of Jinan, Jinan 250022, China
| | - Weiming Lü
- Spintronics Institute, University of Jinan, Jinan 250022, China
| | - Lihui Bai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Yufeng Tian
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Shishen Yan
- Spintronics Institute, University of Jinan, Jinan 250022, China
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
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7
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Son JW, Yang S, Ju TS, Hwang C, Moon KW. Measurement of spin-orbit torque using field counterbalancing in radial current geometry. Sci Rep 2023; 13:19357. [PMID: 37938612 PMCID: PMC10632434 DOI: 10.1038/s41598-023-46658-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: 05/08/2023] [Accepted: 11/03/2023] [Indexed: 11/09/2023] Open
Abstract
Controlling the direction of magnetization with an electric current, rather than a magnetic field, is a powerful technique in spintronics. Spin-orbit torque, which generates an effective magnetic field from the injected current, is a promising method for this purpose. Here we show an approach for quantifying the magnitude of spin-orbit torque from a single magnetic image. To achieve this, we deposited two concentric electrodes on top of the magnetic sample to flow a radial current. By counterbalancing the current effect with an external magnetic field, we can create a stable circular magnetization state. We measure the magnitude of spin-orbit torque from the stable radius, providing a new tool for characterizing spin-orbit torque.
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Affiliation(s)
- Jong Wan Son
- Quantum Spin Team, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - Seungmo Yang
- Quantum Spin Team, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - Tae-Seong Ju
- Quantum Spin Team, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - Chanyong Hwang
- Quantum Spin Team, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea.
| | - Kyoung-Woong Moon
- Quantum Spin Team, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea.
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8
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Zhu L. Switching of Perpendicular Magnetization by Spin-Orbit Torque. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2300853. [PMID: 37004142 DOI: 10.1002/adma.202300853] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 03/16/2023] [Indexed: 06/19/2023]
Abstract
Magnetic materials with strong perpendicular magnetic anisotropy are of great interest for the development of nonvolatile magnetic memory and computing technologies due to their high stabilities at the nanoscale. However, electrical switching of such perpendicular magnetization in an energy-efficient, deterministic, scalable manner has remained a big challenge. This problem has recently attracted enormous efforts in the field of spintronics. Here, recent advances and challenges in the understanding of the electrical generation of spin currents, the switching mechanisms and the switching strategies of perpendicular magnetization, the switching current density by spin-orbit torque of transverse spins, the choice of perpendicular magnetic materials are reviewed, and the progress in prototype perpendicular SOT memory and logic devices toward the goal of energy-efficient, dense, fast perpendicular spin-orbit torque applications is summarized.
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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
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9
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Zhao Q, Zhu Y, Zhang H, Jiang B, Wang Y, Xie T, Lou K, Xia C, Yang H, Bi C. Proximity-Induced Interfacial Room-Temperature Ferromagnetism in Semiconducting Fe 3GeTe 2. ACS APPLIED MATERIALS & INTERFACES 2023; 15:46520-46526. [PMID: 37738105 DOI: 10.1021/acsami.3c09932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
The discoveries of two-dimensional ferromagnetism and magnetic semiconductors highly enrich the magnetic material family for constructing spin-based electronic devices, but with an acknowledged challenge that the Curie temperature (Tc) is usually far below room temperature. Many efforts such as voltage control and magnetic ion doping are currently underway to enhance the functional temperature, in which the involvement of additional electrodes or extra magnetic ions limits their application in practical devices. Here we demonstrate that the magnetic proximity, a robust effect but with elusive mechanisms, can induce room-temperature ferromagnetism at the interface between sputtered Pt and semiconducting Fe3GeTe2, both of which do not show ferromagnetism at 300 K. The independent electrical and magnetization measurements, structure analysis, and control samples with Ta highlighting the role of Pt confirm that the ferromagnetism with the Tc of above 400 K arises from the Fe3GeTe2/Pt interfaces, rather than Fe aggregation or other artificial effects. Moreover, contrary to conventional ferromagnet/Pt structures, the spin current generated by the Pt layer is enhanced more than two times at the Fe3GeTe2/Pt interfaces, indicating the potential applications of the unique proximity effect in building highly efficient spintronic devices. These results may pave a new avenue to create room-temperature functional spin devices based on low-Tc materials and provide clear evidence of magnetic proximity effects by using nonferromagnetic materials.
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Affiliation(s)
- Qianwen Zhao
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingmei Zhu
- 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
| | - Hanying Zhang
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baiqing Jiang
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan Wang
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tunan Xie
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kaihua Lou
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - ChaoChao Xia
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, 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
| | - Chong Bi
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
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10
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Kim G, Lee S, Lee S, Song B, Lee BK, Lee D, Lee JS, Lee MH, Kim YK, Park BG. The Influence of Capping Layers on Tunneling Magnetoresistance and Microstructure in CoFeB/MgO/CoFeB Magnetic Tunnel Junctions upon Annealing. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2591. [PMID: 37764621 PMCID: PMC10534786 DOI: 10.3390/nano13182591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/13/2023] [Accepted: 09/16/2023] [Indexed: 09/29/2023]
Abstract
This study investigates the effects of annealing on the tunnel magnetoresistance (TMR) ratio in CoFeB/MgO/CoFeB-based magnetic tunnel junctions (MTJs) with different capping layers and correlates them with microstructural changes. It is found that the capping layer plays an important role in determining the maximum TMR ratio and the corresponding annealing temperature (Tann). For a Pt capping layer, the TMR reaches ~95% at a Tann of 350 °C, then decreases upon a further increase in Tann. A microstructural analysis reveals that the low TMR is due to severe intermixing in the Pt/CoFeB layers. On the other hand, when introducing a Ta capping layer with suppressed diffusion into the CoFeB layer, the TMR continues to increase with Tann up to 400 °C, reaching ~250%. Our findings indicate that the proper selection of a capping layer can increase the annealing temperature of MTJs so that it becomes compatible with the complementary metal-oxide-semiconductor backend process.
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Affiliation(s)
- Geunwoo Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Soogil Lee
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
- Department of Electronic Engineering, Gachon University, Seongnam 13120, Republic of Korea
| | - Sanghwa Lee
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Byonggwon Song
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon 16678, Republic of Korea
| | - Byung-Kyu Lee
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon 16678, Republic of Korea
| | - Duhyun Lee
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon 16678, Republic of Korea
| | - Jin Seo Lee
- Department of Semiconductor Systems Engineering, Korea University, Seoul 02481, Republic of Korea
| | - Min Hyeok Lee
- Department of Materials Science and Engineering, Korea University, Seoul 02481, Republic of Korea
| | - Young Keun Kim
- Department of Materials Science and Engineering, Korea University, Seoul 02481, Republic of Korea
| | - Byong-Guk Park
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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11
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Yoon JY, Zhang P, Chou CT, Takeuchi Y, Uchimura T, Hou JT, Han J, Kanai S, Ohno H, Fukami S, Liu L. Handedness anomaly in a non-collinear antiferromagnet under spin-orbit torque. NATURE MATERIALS 2023; 22:1106-1113. [PMID: 37537356 DOI: 10.1038/s41563-023-01620-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 06/23/2023] [Indexed: 08/05/2023]
Abstract
Non-collinear antiferromagnets are an emerging family of spintronic materials because they not only possess the general advantages of antiferromagnets but also enable more advanced functionalities. Recently, in an intriguing non-collinear antiferromagnet Mn3Sn, where the octupole moment is defined as the collective magnetic order parameter, spin-orbit torque (SOT) switching has been achieved in seemingly the same protocol as in ferromagnets. Nevertheless, it is fundamentally important to explore the unknown octupole moment dynamics and contrast it with the magnetization vector of ferromagnets. Here we report a handedness anomaly in the SOT-driven dynamics of Mn3Sn: when spin current is injected, the octupole moment rotates in the opposite direction to the individual moments, leading to a SOT switching polarity distinct from ferromagnets. By using second-harmonic and d.c. magnetometry, we track the SOT effect onto the octupole moment during its rotation and reveal that the handedness anomaly stems from the interactions between the injected spin and the unique chiral-spin structure of Mn3Sn. We further establish the torque balancing equation of the magnetic octupole moment and quantify the SOT efficiency. Our finding provides a guideline for understanding and implementing the electrical manipulation of non-collinear antiferromagnets, which in nature differs from the well-established collinear magnets.
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Affiliation(s)
- Ju-Young Yoon
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
- Graduate School of Engineering, Tohoku University, Sendai, Japan
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Pengxiang Zhang
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Chung-Tao Chou
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yutaro Takeuchi
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
| | - Tomohiro Uchimura
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
- Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Justin T Hou
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jiahao Han
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan.
| | - Shun Kanai
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
- Graduate School of Engineering, Tohoku University, Sendai, Japan
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, Sendai, Japan
- Division for the Establishment of Frontier Sciences of Organization for Advanced Studies, Tohoku University, Sendai, Japan
| | - Hideo Ohno
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
- Graduate School of Engineering, Tohoku University, Sendai, Japan
- WPI-Advanced Institute for Materials Research, 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
| | - Shunsuke Fukami
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan.
- Graduate School of Engineering, Tohoku University, Sendai, Japan.
- WPI-Advanced Institute for Materials Research, 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.
- Inamori Research Institute for Science, Kyoto, Japan.
| | - Luqiao Liu
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
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12
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Wang H, Wu H, Zhang J, Liu Y, Chen D, Pandey C, Yin J, Wei D, Lei N, Shi S, Lu H, Li P, Fert A, Wang KL, Nie T, Zhao W. Room temperature energy-efficient spin-orbit torque switching in two-dimensional van der Waals Fe 3GeTe 2 induced by topological insulators. Nat Commun 2023; 14:5173. [PMID: 37620355 PMCID: PMC10449904 DOI: 10.1038/s41467-023-40714-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 08/07/2023] [Indexed: 08/26/2023] Open
Abstract
Two-dimensional (2D) ferromagnetic materials with unique magnetic properties have great potential for next-generation spintronic devices with high flexibility, easy controllability, and high heretointegrability. However, realizing magnetic switching with low power consumption at room temperature is challenging. Here, we demonstrate the room-temperature spin-orbit torque (SOT) driven magnetization switching in an all-van der Waals (vdW) heterostructure using an optimized epitaxial growth approach. The topological insulator Bi2Te3 not only raises the Curie temperature of Fe3GeTe2 (FGT) through interfacial exchange coupling but also works as a spin current source allowing the FGT to switch at a low current density of ~2.2×106 A/cm2. The SOT efficiency is ~2.69, measured at room temperature. The temperature and thickness-dependent SOT efficiency prove that the larger SOT in our system mainly originates from the nontrivial topological origin of the heterostructure. Our experiments enable an all-vdW SOT structure and provides a solid foundation for the implementation of room-temperature all-vdW spintronic devices in the future.
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Affiliation(s)
- Haiyu Wang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China
- Shenyuan Honors College, Beihang University, Beijing, China
| | - Hao Wu
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, USA
| | - Jie Zhang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China
| | - Yingjie Liu
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China
| | - Dongdong Chen
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing, China
| | - Chandan Pandey
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China
| | - Jialiang Yin
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China
| | - Dahai Wei
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing, China
| | - Na Lei
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China
| | - Shuyuan Shi
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China
| | - Haichang Lu
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China
| | - Peng Li
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA
| | - Albert Fert
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, University of Paris-Saclay, Palaiseau, France
| | - Kang L Wang
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, USA
| | - Tianxiao Nie
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China.
| | - Weisheng Zhao
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China.
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13
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Li T, Liu L, Li X, Zhao X, An H, Ando K. Giant Orbital-to-Spin Conversion for Efficient Current-Induced Magnetization Switching of Ferrimagnetic Insulator. NANO LETTERS 2023; 23:7174-7179. [PMID: 37466330 DOI: 10.1021/acs.nanolett.3c02104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
It has long been believed that the attachment of two heavy metals such as Ta and Pt with opposite spin Hall angles results in a weakened net torque generation efficiency in magnetization switching devices. Here, we report a giant orbital-to-spin conversion in Ta/Pt/Tm3Fe5O12 (TmIG) heterostructures. We show that the torque generation efficiency is enhanced by an order of magnitude in the Ta/Pt/TmIG trilayer compared to that in the Pt/TmIG bilayer. This enhancement is further evidenced by the fact that the critical current density for the magnetization switching of the Ta/Pt/TmIG is an order of magnitude smaller than that of the Pt/TmIG. It is found that the orbital current generated from Ta through the orbital Hall effect (OHE) is converted to the spin current in the interior of Pt. Our discovery offers an extraordinary approach to enhance the torque generation for magnetization switching of insulators and provides an important piece of information for orbitronics.
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Affiliation(s)
- Tianhui Li
- College of New Materials and New Energies, Shenzhen Technology University, Shenzhen 518118, P. R. China
| | - Long Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, P. R. China
| | - Xiaoguang Li
- College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, P. R. China
| | - Xiaotian Zhao
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, P. R. China
| | - Hongyu An
- College of New Materials and New Energies, Shenzhen Technology University, Shenzhen 518118, P. R. China
| | - Kazuya Ando
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan
- Keio Institute of Pure and Applied Science, Keio University, Yokohama 223-8522, Japan
- Center for Spintronics Research Network, Keio University, Yokohama 223-8522, Japan
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14
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Mohan JR, Mathew AJ, Nishimura K, Feng R, Medwal R, Gupta S, Rawat RS, Fukuma Y. Classification tasks using input driven nonlinear magnetization dynamics in spin Hall oscillator. Sci Rep 2023; 13:7909. [PMID: 37193725 DOI: 10.1038/s41598-023-34849-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 05/09/2023] [Indexed: 05/18/2023] Open
Abstract
The inherent nonlinear magnetization dynamics in spintronic devices make them suitable candidates for neuromorphic hardware. Among spintronic devices, spin torque oscillators such as spin transfer torque oscillators and spin Hall oscillators have shown the capability to perform recognition tasks. In this paper, with the help of micromagnetic simulations, we model and demonstrate that the magnetization dynamics of a single spin Hall oscillator can be nonlinearly transformed by harnessing input pulse streams and can be utilized for classification tasks. The spin Hall oscillator utilizes the microwave spectral characteristics of its magnetization dynamics for processing a binary data input. The spectral change due to the nonlinear magnetization dynamics assists in real-time feature extraction and classification of 4-binary digit input patterns. The performance was tested for the classification of the standard MNIST handwritten digit data set and achieved an accuracy of 83.1% in a simple linear regression model. Our results suggest that modulating time-driven input data can generate diverse magnetization dynamics in the spin Hall oscillator that can be suitable for temporal or sequential information processing.
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Affiliation(s)
- John Rex Mohan
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, 820-8502, Japan
| | - Arun Jacob Mathew
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, 820-8502, Japan
| | - Kazuma Nishimura
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, 820-8502, Japan
| | - Ruoyan Feng
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, 820-8502, Japan
| | - Rohit Medwal
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore, 637617, Singapore
- Department of Physics, Indian Institute of Technology, Kanpur, 208016, India
| | - Surbhi Gupta
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore, 637617, Singapore
- Department of Physics, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, 211004, India
| | - Rajdeep Singh Rawat
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore, 637617, Singapore
| | - Yasuhiro Fukuma
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, 820-8502, Japan.
- Research Center for Neuromorphic AI Hardware, Kyushu Institute of Technology, Kitakyushu, 808-0196, Japan.
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15
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Kumar D, Chung HJ, Chan J, Jin T, Lim ST, Parkin SSP, Sbiaa R, Piramanayagam SN. Ultralow Energy Domain Wall Device for Spin-Based Neuromorphic Computing. ACS NANO 2023; 17:6261-6274. [PMID: 36944594 DOI: 10.1021/acsnano.2c09744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Neuromorphic computing (NC) is gaining wide acceptance as a potential technology to achieve low-power intelligent devices. To realize NC, researchers investigate various types of synthetic neurons and synaptic devices, such as memristors and spintronic devices. In comparison, spintronics-based neurons and synapses have potentially higher endurance. However, for realizing low-power devices, domain wall (DW) devices that show DW motion at low energies─typically below pJ/bit─are favored. Here, we demonstrate DW motion at current densities as low as 106 A/m2 by engineering the β-W spin-orbit coupling (SOC) material. With our design, we achieve ultralow pinning fields and current density reduction by a factor of 104. The energy required to move the DW by a distance of about 18.6 μm is 0.4 fJ, which translates into the energy consumption of 27 aJ/bit for a bit-length of 1 μm. With a meander DW device configuration, we have established a controlled DW motion for synapse applications and have shown the direction to make ultralow energy spin-based neuromorphic elements.
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Affiliation(s)
- Durgesh Kumar
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Hong Jing Chung
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, 138634, Singapore
| | - JianPeng Chan
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Tianli Jin
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Sze Ter Lim
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, 138634, Singapore
| | - Stuart S P Parkin
- Max Planck Institute for Microstructure Physics, 06120 Halle, Germany
| | - Rachid Sbiaa
- Department of Physics, Sultan Qaboos University, P.O. Box 36, PC 123, Muscat, Oman
| | - S N Piramanayagam
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
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16
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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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17
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Zhao M, Wang L, Zhao Y, Du Y, He Z, Chen K, Luo Z, Yan W, Li Q, Wang C, Jiang Z, Liu M, Zhou Z. Deterministic Magnetic Switching in Perpendicular Magnetic Trilayers Through Sunlight-Induced Photoelectron Injection. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023:e2301955. [PMID: 36970816 DOI: 10.1002/smll.202301955] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 03/08/2023] [Indexed: 06/18/2023]
Abstract
Finding an energy-efficient way of switching magnetization is crucial in spintronic devices, such as memories. Usually, spins are manipulated by spin-polarized currents or voltages in various ferromagnetic heterostructures; however, their energy consumption is relatively large. Here, a sunlight control of perpendicular magnetic anisotropy (PMA) in Pt (0.8 nm)/Co (0.65 nm)/Pt (2.5 nm)/PN Si heterojunction in an energy-efficient manner is proposed. The coercive field (HC ) is altered from 261 to 95 Oe (64% variation) under sunlight illumination, enabling a nearly 180° deterministic magnetization switching reversibly with a 140 Oe magnetic bias assistant. The element-resolved X-ray circular dichroism measurement reveals different L3 and L2 edge signals of the Co layer with or without sunlight, suggesting a photoelectron-induced redistribution of the orbital and spin moment in Co magnetization. The first-principle calculations also reveal that the photo-induced electrons shift the Fermi level of electrons and enhance the in-plane Rashba field around the Co/Pt interfaces, leading to a weakened PMA and corresponding HC decreasing and magnetization switching accordingly. The sunlight control of PMA may provide an alternative way for magnetic recording, which is energy efficient and would reduce the Joule heat from the high switching current.
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Affiliation(s)
- Meng Zhao
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering, State Key Laboratory for Manufacturing Systems Engineering, The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Lei Wang
- Center for Spintronics and Quantum Systems, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, No. 28 Xianning West Road, Xi'an, Shaanxi, 710049, China
| | - Yifan Zhao
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering, State Key Laboratory for Manufacturing Systems Engineering, The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Yujing Du
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering, State Key Laboratory for Manufacturing Systems Engineering, The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Zhexi He
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering, State Key Laboratory for Manufacturing Systems Engineering, The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Kai Chen
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, 230029, China
| | - Zhenlin Luo
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, 230029, China
| | - Wensheng Yan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, 230029, China
| | - Qian Li
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, 230029, China
| | - Chenying Wang
- State Key Laboratory for Manufacturing Systems Engineering, Collaborative Innovation Center of High-End Manufacturing Equipment, The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Zhuangde Jiang
- State Key Laboratory for Manufacturing Systems Engineering, Collaborative Innovation Center of High-End Manufacturing Equipment, The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Ming Liu
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering, State Key Laboratory for Manufacturing Systems Engineering, The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Ziyao Zhou
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering, State Key Laboratory for Manufacturing Systems Engineering, The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an, 710049, China
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18
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Meng Y, Jiang L, Zheng Y. Spin filters based on two-dimensional materials Co 2Si and Cu 2Si. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:195001. [PMID: 36863029 DOI: 10.1088/1361-648x/acc0c0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 03/02/2023] [Indexed: 02/17/2024]
Abstract
Spintronic devices have several advantages compared with conventional electronic devices, including non-volatility, faster data processing speed, higher integration densities, less electric power consumption and so on. However, we still face challenges for efficiently generating and injecting pure spin polarized current. In this work, we utilize two kinds of two-dimensional materials Co2Si and Cu2Si with both lattice match and band match to construct devices and then research their spin filter efficiency. The spin filter efficiency can be improved effectively either by an appropriate gate voltage at Co2Si region, or by series connection. In both cases the filter efficiencies are much larger than two-dimensional prepared Fe3GeTe2spin valve and ferromagnetic metallic chairlike O-graphene-H. Also at a quite small bias, we obtain a comparable spin polarized current as those obtained in Fe3GeTe2spin valve and O-graphene-H obtained at a much larger bias.
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Affiliation(s)
- Yexuan Meng
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, People's Republic of China
| | - Liwei Jiang
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, People's Republic of China
| | - Yisong Zheng
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, People's Republic of China
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19
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Zhang Z, Cheng M, Fan Z, Liu Y, Wang D, Wang K, Xiong R, Lu Z. The high magnetoresistance performance of epitaxial half-metallic CrO 2-based magnetic junctions. Phys Chem Chem Phys 2023; 25:1848-1857. [PMID: 36602084 DOI: 10.1039/d2cp05015c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Half-metallic chromium dioxide (CrO2) is an ideal spintronic material due to its near-full spin polarization and ultralow Gilbert damping at room temperature. Based on theoretical calculations, we found that the tunneling magnetoresistance (TMR) ratios of the CrO2/XO2/CrO2 (X= Ti and Sn) magnetic tunnel junctions (MTJs) can reach up to the order of magnitude of 105%, and the magnetoresistance (MR) ratio of CrO2/RuO2/CrO2 magnetic junctions (MJs) can reach the order of magnitude of 104%. In addition, we succeeded in fabricating epitaxial CrO2-based MTJs (CrO2/TiO2/CrO2 and CrO2/TiO2/Co2FeAl) with TiO2 tunnel barriers of varying thickness. Evident TMR effects were observed for all CrO2-based MTJs with the highest MR ratio of 8.55% for the CrO2/TiO2/Co2FeAl MTJ at 10 K. The MR ratios of CrO2-based MTJs in our studies were lower than theoretical expectations, which could be due to the possible mixture of interface atoms and Cr magnetization reversal. Moreover, the existence of oxygen vacancies in the TiO2 tunnel barrier also weakened the TMR effect significantly due to increased spin scattering, and the annealing treatment in an oxygen atmosphere led to an increase in the MR ratio of the CrO2/TiO2/Co2FeAl MTJ by about 33% in comparison with the unannealed MTJ, which is consistent with theoretical calculations.
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Affiliation(s)
- Zhenhua Zhang
- The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China. .,School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Ming Cheng
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China.
| | - Zhiqiang Fan
- School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114, China
| | - Yong Liu
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China.
| | - Dengjing Wang
- College of Science, Wuhan University of Science and Technology, Wuhan 430065, China
| | - Ke Wang
- School of Mechanical and Electronic Engineering, East China University of Technology, Nanchang 330013, China
| | - Rui Xiong
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China.
| | - Zhihong Lu
- The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China. .,School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China
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20
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Xie X, Wang X, Wang W, Zhao X, Bai L, Chen Y, Tian Y, Yan S. Engineering Spin Configurations of Synthetic Antiferromagnet by Controlling Long-Range Oscillatory Interlayer Coupling and Neighboring Ferrimagnetic Coupling. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208275. [PMID: 36268544 DOI: 10.1002/adma.202208275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Controllable manipulation of specific spin configurations of magnetic materials is the key to constructing functional spintronic devices. Here, it is demonstrated by integrating the merits of ferromagnetic, ferrimagnetic, and antiferromagnetic spin configurations into one synthetic antiferromagnetic (SAF) heterostructure by controlling both long-range oscillatory interlayer coupling and neighboring ferrimagnetic coupling. A controllable manipulation of four types of spin configurations of the Pt/[Co/Pt/Co]/Ru/CoTb SAF heterostructures composed of ferromagnetic Co/Pt/Co and ferrimagnetic CoTb layers is successfully achieved. In particular, the compensated magnetization, enhanced anomalous Hall resistance in the remanence state, wide-temperature spin-orbit torque switching of magnetization, and high immunity to the external magnetic field are simultaneously obtained in one of the SAF heterojunctions with macroscopic interlayer antiferromagnetic coupling. This design concept of engineering spin configurations may enable efficient spin manipulation for customized memory and logic applications.
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Affiliation(s)
- Xuejie Xie
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Xiujuan Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Wei Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Xiaonan Zhao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Lihui Bai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Yanxue Chen
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Yufeng Tian
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Shishen Yan
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
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21
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Lee S, Kang J, Kim JM, Kim N, Han D, Lee T, Ko S, Yang J, Lee S, Lee S, Koh D, Kang MG, Lee J, Noh S, Lee H, Kwon J, Baek SHC, Kim KJ, Park BG. Spintronic Physical Unclonable Functions Based on Field-Free Spin-Orbit-Torque Switching. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2203558. [PMID: 36122902 DOI: 10.1002/adma.202203558] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 08/25/2022] [Indexed: 06/15/2023]
Abstract
Physical unclonable function (PUFs) utilize inherent random physical variations of solid-state devices and are a core ingredient of hardware security primitives. PUFs promise more robust information security than that provided by the conventional software-based approaches. While silicon- and memristor-based PUFs are advancing, their reliability and scalability require further improvements. These are currently limited by output fluctuations and associated additional peripherals. Here, highly reliable spintronic PUFs that exploit field-free spin-orbit-torque switching in IrMn/CoFeB/Ta/CoFeB structures are demonstrated. It is shown that the stochastic switching polarity of the perpendicular magnetization of the top CoFeB can be achieved by manipulating the exchange bias directions of the bottom IrMn/CoFeB. This serves as an entropy source for the spintronic PUF, which is characterized by high entropy, uniqueness, reconfigurability, and digital output. Furthermore, the device ensures a zero bit-error-rate under repetitive operations and robustness against external magnetic fields, and offers scalable and energy-efficient device implementations.
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Affiliation(s)
- Soogil Lee
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Jaimin Kang
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Jeong-Mok Kim
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Namhee Kim
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Donghyeon Han
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | | | - San Ko
- Department of Physics, KAIST, Daejeon, 34141, Korea
| | - Jiseok Yang
- Department of Physics, KAIST, Daejeon, 34141, Korea
| | - Sanghwa Lee
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Sungjun Lee
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Daekyu Koh
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Min-Gu Kang
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Jisung Lee
- Research & Development Division, Hyundai Motor Company, Hwaseong, 18280, Korea
| | - Sujung Noh
- Research & Development Division, Hyundai Motor Company, Hwaseong, 18280, Korea
| | - Hansaem Lee
- Research & Development Division, Hyundai Motor Company, Hwaseong, 18280, Korea
| | - JoonHyun Kwon
- Research & Development Division, Hyundai Motor Company, Hwaseong, 18280, Korea
| | | | - Kab-Jin Kim
- Department of Physics, KAIST, Daejeon, 34141, Korea
| | - Byong-Guk Park
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
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22
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Chu R, Liu L, Cui B, Liu W, An T, Ren X, Miao T, Cheng B, Hu J. Electrical Control of Spin Hall Effect in Pt by Hydrogen Ion Adsorption and Desorption. ACS NANO 2022; 16:16077-16084. [PMID: 36130100 DOI: 10.1021/acsnano.2c04297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The manipulation of charge-to-spin current conversion and spin-orbit torque (SOT) is of great interest due to its profound physics and potential applications. Controlling the spin current through the electric field provides a perspective for highly efficient SOT devices. Here, we use H2O-doped ionic liquid gating to realize the reversible and nonvolatile manipulation of the spin Hall effect of Pt, and the spin Hall angle can be modulated by 48% within an accessible gate voltage range. The increase in the spin Hall angle is demonstrated to be caused by the adsorption of hydrogen ions on the Pt surface and the consequent enhancement of the spin Hall conductivity under positive voltage. Furthermore, the enhancement of the spin Hall angle is beneficial to reduce the critical current density for driving the domain wall motion. These results supply a method for the dynamic control of the charge-to-spin current conversion, which will promote the development of spintronic devices driven by electric fields.
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Affiliation(s)
- Ruiyue Chu
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, China
| | - Liang Liu
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, China
| | - Bin Cui
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, China
| | - Weikang Liu
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, China
| | - Taiyu An
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, China
| | - Xue Ren
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, China
| | - Tingting Miao
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, China
| | - Bin Cheng
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, China
| | - Jifan Hu
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, China
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23
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Huang Q, Guan C, Fan Y, Zhao X, Han X, Dong Y, Xie X, Zhou T, Bai L, Peng Y, Tian Y, Yan S. Field-Free Magnetization Switching in a Ferromagnetic Single Layer through Multiple Inversion Asymmetry Engineering. ACS NANO 2022; 16:12462-12470. [PMID: 35866710 DOI: 10.1021/acsnano.2c03756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A simple, reliable, and self-switchable spin-orbit torque (SOT)-induced magnetization switching in a ferromagnetic single layer is needed for the development of next generation fully electrical controllable spintronic devices. In this work, field-free SOT-induced magnetization switching in a CoPt single layer is realized by broken multiple inversion symmetry through simultaneously introducing both oblique sputtering and a vertical composition gradient. A quantitative analysis indicates that multiple inversion asymmetries can produce dynamical bias fields along both z- and x-axes, leading to the observed field-free deterministic magnetization switching. Our study provides a method to accomplish fully electrical manipulation of magnetization in a ferromagnetic single layer without the external magnetic field and auxiliary heavy metal layer, enabling flexible design for future spin-orbit torque-based memory and logic devices.
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Affiliation(s)
- Qikun Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Chaoshuai Guan
- Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou 730000, China
| | - Yibo Fan
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Xiaonan Zhao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Xiang Han
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Yanan Dong
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Xuejie Xie
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Tie Zhou
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Lihui Bai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Yong Peng
- Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, School of Materials and Energy and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou 730000, China
| | - Yufeng Tian
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Shishen Yan
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
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24
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Park HJ, Ko HW, Go G, Oh JH, Kim KW, Lee KJ. Spin Swapping Effect of Band Structure Origin in Centrosymmetric Ferromagnets. PHYSICAL REVIEW LETTERS 2022; 129:037202. [PMID: 35905335 DOI: 10.1103/physrevlett.129.037202] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 04/19/2022] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
We theoretically demonstrate the spin swapping effect of band structure origin in centrosymmetric ferromagnets. It is mediated by an orbital degree of freedom but does not require inversion asymmetry or impurity spin-orbit scattering. Analytic and tight-binding models reveal that it originates mainly from k points where bands with different spins and different orbitals are nearly degenerate, and thus it has no counterpart in normal metals. First-principle calculations for centrosymmetric 3d transition-metal ferromagnets show that the spin swapping conductivity of band structure origin can be comparable in magnitude to the intrinsic spin Hall conductivity of Pt. Our theory generalizes transverse spin currents generated by ferromagnets and emphasizes the important role of the orbital degree of freedom in describing spin-orbit-coupled transport in centrosymmetric materials.
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Affiliation(s)
- Hyeon-Jong Park
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
| | - Hye-Won Ko
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Gyungchoon Go
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Jung Hyun Oh
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Korea
| | - Kyoung-Whan Kim
- Center of Spintronics, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Kyung-Jin Lee
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
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25
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Choi E, Sim KI, Burch KS, Lee YH. Emergent Multifunctional Magnetic Proximity in van der Waals Layered Heterostructures. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2200186. [PMID: 35596612 PMCID: PMC9313546 DOI: 10.1002/advs.202200186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 04/01/2022] [Indexed: 05/10/2023]
Abstract
Proximity effect, which is the coupling between distinct order parameters across interfaces of heterostructures, has attracted immense interest owing to the customizable multifunctionalities of diverse 3D materials. This facilitates various physical phenomena, such as spin order, charge transfer, spin torque, spin density wave, spin current, skyrmions, and Majorana fermions. These exotic physics play important roles for future spintronic applications. Nevertheless, several fundamental challenges remain for effective applications: unavoidable disorder and lattice mismatch limits in the growth process, short characteristic length of proximity, magnetic fluctuation in ultrathin films, and relatively weak spin-orbit coupling (SOC). Meanwhile, the extensive library of atomically thin, 2D van der Waals (vdW) layered materials, with unique characteristics such as strong SOC, magnetic anisotropy, and ultraclean surfaces, offers many opportunities to tailor versatile and more effective functionalities through proximity effects. Here, this paper focuses on magnetic proximity, i.e., proximitized magnetism and reviews the engineering of magnetism-related functionalities in 2D vdW layered heterostructures for next-generation electronic and spintronic devices. The essential factors of magnetism and interfacial engineering induced by magnetic layers are studied. The current limitations and future challenges associated with magnetic proximity-related physics phenomena in 2D heterostructures are further discussed.
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Affiliation(s)
- Eun‐Mi Choi
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS)Sungkyunkwan University (SKKU)Suwon16419Republic of Korea
| | - Kyung Ik Sim
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS)Sungkyunkwan University (SKKU)Suwon16419Republic of Korea
| | - Kenneth S. Burch
- Department of PhysicsBoston College140 Commonwealth AveChestnut HillMA02467‐3804USA
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS)Sungkyunkwan University (SKKU)Suwon16419Republic of Korea
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419Republic of Korea
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26
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Fan Y, Han X, Zhao X, Dong Y, Chen Y, Bai L, Yan S, Tian Y. Programmable Spin-Orbit Torque Multistate Memory and Spin Logic Cell. ACS NANO 2022; 16:6878-6885. [PMID: 35349269 DOI: 10.1021/acsnano.2c01930] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Controllable spin-orbit torque based nonvolatile memory is highly desired for constructing energy efficient reconfigurable logic-in-memory computing suitable for emerging data-intensive applications. Here, we report our exploration of the IrMn/Co/Ru/CoPt/CoO heterojunction as a potential candidate for applications in both multistate memory and programmable spin logic. The studied heterojunction can be programmed into four different magnetic configurations at will by tuning both the in-plane exchange bias at the interface of IrMn and Co layers and the out-of-plane exchange bias at the interface of CoPt and CoO layers. Moreover, on the basis of the controllable exchange bias effect, 10 states of nonvolatile memory and multiple logic-in-memory functions have been demonstrated. Our findings indicate that IrMn/Co/Ru/CoPt/CoO multilayered structures can be used as a building block for next-generation logic-in-memory and multifunctional multidimensional spintronic devices.
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Affiliation(s)
- Yibo Fan
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Xiang Han
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Xiaonan Zhao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Yanan Dong
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Yanxue Chen
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Lihui Bai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Shishen Yan
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
- Spintronics Institute, University of Jinan, Jinan 250022, China
| | - Yufeng Tian
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
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27
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Giant tunable spin Hall angle in sputtered Bi 2Se 3 controlled by an electric field. Nat Commun 2022; 13:1650. [PMID: 35347125 PMCID: PMC8960771 DOI: 10.1038/s41467-022-29281-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 02/23/2022] [Indexed: 11/21/2022] Open
Abstract
Finding an effective way to greatly tune spin Hall angle in a low power manner is of fundamental importance for tunable and energy-efficient spintronic devices. Recently, topological insulator of Bi2Se3, having a large intrinsic spin Hall angle, show great capability to generate strong current-induced spin-orbit torques. Here we demonstrate that the spin Hall angle in Bi2Se3 can be effectively tuned asymmetrically and even enhanced about 600% reversibly by applying a bipolar electric field across the piezoelectric substrate. We reveal that the enhancement of spin Hall angle originates from both the charge doping and piezoelectric strain effet on the spin Berry curvature near Fermi level in Bi2Se3. Our findings provide a platform for achieving low power consumption and tunable spintronic devices. Controlling the spin Hall angle is significant to tunable and energy-efficient spintronic devices. Here, the authors demonstrate that the spin Hall angle in Bi2Se3 can be tuned and even enhanced about 600% reversibly by the electric field.
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28
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Shin I, Cho WJ, An ES, Park S, Jeong HW, Jang S, Baek WJ, Park SY, Yang DH, Seo JH, Kim GY, Ali MN, Choi SY, Lee HW, Kim JS, Kim SD, Lee GH. Spin-Orbit Torque Switching in an All-Van der Waals Heterostructure. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2101730. [PMID: 34908193 DOI: 10.1002/adma.202101730] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 12/09/2021] [Indexed: 06/14/2023]
Abstract
Current-induced control of magnetization in ferromagnets using spin-orbit torque (SOT) has drawn attention as a new mechanism for fast and energy efficient magnetic memory devices. Energy-efficient spintronic devices require a spin-current source with a large SOT efficiency (ξ) and electrical conductivity (σ), and an efficient spin injection across a transparent interface. Herein, single crystals of the van der Waals (vdW) topological semimetal WTe2 and vdW ferromagnet Fe3 GeTe2 are used to satisfy the requirements in their all-vdW-heterostructure with an atomically sharp interface. The results exhibit values of ξ ≈ 4.6 and σ ≈ 2.25 × 105 Ω-1 m-1 for WTe2 . Moreover, the significantly reduced switching current density of 3.90 × 106 A cm-2 at 150 K is obtained, which is an order of magnitude smaller than those of conventional heavy-metal/ferromagnet thin films. These findings highlight that engineering vdW-type topological materials and magnets offers a promising route to energy-efficient magnetization control in SOT-based spintronics.
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Affiliation(s)
- Inseob Shin
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Won Joon Cho
- Material Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Eun-Su An
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Sungyu Park
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Hyeon-Woo Jeong
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Seong Jang
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Woon Joong Baek
- Material Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Seong Yong Park
- Material Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Dong-Hwan Yang
- Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Pohang, 37673, Republic of Korea
| | - Jun Ho Seo
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Gi-Yeop Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Pohang, 37673, Republic of Korea
| | - Mazhar N Ali
- Max Plank Institute for Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Si-Young Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Pohang, 37673, Republic of Korea
| | - Hyun-Woo Lee
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Asia Pacific Center for Theoretical Physics, 77 Cheongam-Ro, Pohang, 37673, Republic of Korea
| | - Jun Sung Kim
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Sung Dug Kim
- Material Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Gil-Ho Lee
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Asia Pacific Center for Theoretical Physics, 77 Cheongam-Ro, Pohang, 37673, Republic of Korea
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29
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Ji YT, Tan X, Yue XY, Sun Y, Wang YY, Liang H, Li Q, Sun X, Wu DD. Strain-induced spin-gapless semiconductors and pure thermal spin-current in magnetic black arsenic-phosphorus monolayer. Phys Chem Chem Phys 2022; 24:13897-13904. [DOI: 10.1039/d2cp01108e] [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
Spin-gapless semiconductor (SGS) materials are regarded as the most promising candidates for ideal massless and dissipationless states towards low-power spintronics device application. Here, we propose a spin-gapless semiconducting black arsenic-phosphorus...
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Electric-field control of field-free spin-orbit torque switching via laterally modulated Rashba effect in Pt/Co/AlO x structures. Nat Commun 2021; 12:7111. [PMID: 34876578 PMCID: PMC8651747 DOI: 10.1038/s41467-021-27459-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/20/2021] [Indexed: 11/25/2022] Open
Abstract
Spin-orbit coupling effect in structures with broken inversion symmetry, known as the Rashba effect, facilitates spin-orbit torques (SOTs) in heavy metal/ferromagnet/oxide structures, along with the spin Hall effect. Electric-field control of the Rashba effect is established for semiconductor interfaces, but it is challenging in structures involving metals owing to the screening effect. Here, we report that the Rashba effect in Pt/Co/AlOx structures is laterally modulated by electric voltages, generating out-of-plane SOTs. This enables field-free switching of the perpendicular magnetization and electrical control of the switching polarity. Changing the gate oxide reverses the sign of out-of-plane SOT while maintaining the same sign of voltage-controlled magnetic anisotropy, which confirms the Rashba effect at the Co/oxide interface is a key ingredient of the electric-field modulation. The electrical control of SOT switching polarity in a reversible and non-volatile manner can be utilized for programmable logic operations in spintronic logic-in-memory devices. A major challenge for spin based electronics is the electrical control of magnetization. Here, Kang et al demonstrate how electric field control of the Rashba effect in a Pt/Co/AlOx can enable control of the spin-orbit torque and allow for field free switching of the magnetization.
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Current-induced manipulation of exchange bias in IrMn/NiFe bilayer structures. Nat Commun 2021; 12:6420. [PMID: 34741042 PMCID: PMC8571404 DOI: 10.1038/s41467-021-26678-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 10/14/2021] [Indexed: 11/30/2022] Open
Abstract
The electrical control of antiferromagnetic moments is a key technological goal of antiferromagnet-based spintronics, which promises favourable device characteristics such as ultrafast operation and high-density integration as compared to conventional ferromagnet-based devices. To date, the manipulation of antiferromagnetic moments by electric current has been demonstrated in epitaxial antiferromagnets with broken inversion symmetry or antiferromagnets interfaced with a heavy metal, in which spin-orbit torque (SOT) drives the antiferromagnetic domain wall. Here, we report current-induced manipulation of the exchange bias in IrMn/NiFe bilayers without a heavy metal. We show that the direction of the exchange bias is gradually modulated up to ±22 degrees by an in-plane current, which is independent of the NiFe thickness. This suggests that spin currents arising in the IrMn layer exert SOTs on uncompensated antiferromagnetic moments at the interface which then rotate the antiferromagnetic moments. Furthermore, the memristive features are preserved in sub-micron devices, facilitating nanoscale multi-level antiferromagnetic spintronic devices. Antiferromagnets have great promise for spin-based information processing, offering both high operation speed, and an immunity to stray fields. Here, Kang et al demonstrate electrical manipulation of the exchange-bias, without the need for a heavy metal layer.
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Abstract
Giant spin-orbit torque (SOT) from topological insulators (TIs) provides an energy efficient writing method for magnetic memory, which, however, is still premature for practical applications due to the challenge of the integration with magnetic tunnel junctions (MTJs). Here, we demonstrate a functional TI-MTJ device that could become the core element of the future energy-efficient spintronic devices, such as SOT-based magnetic random-access memory (SOT-MRAM). The state-of-the-art tunneling magnetoresistance (TMR) ratio of 102% and the ultralow switching current density of 1.2 × 105 A cm−2 have been simultaneously achieved in the TI-MTJ device at room temperature, laying down the foundation for TI-driven SOT-MRAM. The charge-spin conversion efficiency θSH in TIs is quantified by both the SOT-induced shift of the magnetic switching field (θSH = 1.59) and the SOT-induced ferromagnetic resonance (ST-FMR) (θSH = 1.02), which is one order of magnitude larger than that in conventional heavy metals. These results inspire a revolution of SOT-MRAM from classical to quantum materials, with great potential to further reduce the energy consumption. It remains challenging to integrate topological insulators (TI) with magnetic tunnel junctions (MTJ) for spintronics applications. Here, the authors achieve a large tunneling magnetoresistance ratio and a low switching current density in a TI-MTJ device at room temperature, very promising for TI-driven magnetic memory.
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Tang W, Liu H, Li Z, Pan A, Zeng Y. Spin-Orbit Torque in Van der Waals-Layered Materials and Heterostructures. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100847. [PMID: 34323390 PMCID: PMC8456225 DOI: 10.1002/advs.202100847] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/03/2021] [Indexed: 06/13/2023]
Abstract
Spin-orbit torque (SOT) opens an efficient and versatile avenue for the electrical manipulation of magnetization in spintronic devices. The enhancement of SOT efficiency and reduction of power consumption are key points for the implementation of high-performance SOT devices, which strongly rely on the spin-orbit coupling (SOC) strength and magnetic properties of ferromagnetic/non-magnetic heterostructures. Recently, van der Waals-layered materials have shown appealing properties for use in efficient SOT applications. On the one hand, transition-metal dichalcogenides, topological insulators, and graphene-based heterostructures possess appreciable SOC strength. This feature can efficiently converse the charge current into spin current and result in large SOT. On the other hand, the newly discovered layered magnetic materials provide ultra-thin and gate-tunable ferromagnetic candidates for high-performance SOT devices. In this review, the latest advancements of SOT research in various layered materials are summarized. First, a brief introduction of SOT is given. Second, SOT studies of various layered materials and heterostructures are summarized. Subsequently, progresses on SOT-induced magnetization switching are presented. Finally, current challenges and prospects for future development are suggested.
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Affiliation(s)
- Wei Tang
- Key laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen518060China
| | - Haoliang Liu
- State Key Laboratory on Tunable Laser TechnologyMinistry of Industry and Information Technology Key Lab of Micro‐Nano Optoelectronic Information SystemSchool of ScienceHarbin Institute of TechnologyShenzhen518055China
| | - Zhe Li
- State Key Laboratory on Tunable Laser TechnologyMinistry of Industry and Information Technology Key Lab of Micro‐Nano Optoelectronic Information SystemSchool of ScienceHarbin Institute of TechnologyShenzhen518055China
| | - Anlian Pan
- Key Laboratory for Micro‐Nano Physics and Technology of Hunan ProvinceCollege of Materials Science and EngineeringHunan UniversityChangsha410082China
| | - Yu‐Jia Zeng
- Key laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen518060China
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Hassan M, Laureti S, Rinaldi C, Fagiani F, Varotto S, Barucca G, Schmidt NY, Varvaro G, Albrecht M. Perpendicularly magnetized Co/Pd-based magneto-resistive heterostructures on flexible substrates. NANOSCALE ADVANCES 2021; 3:3076-3084. [PMID: 36133649 PMCID: PMC9418425 DOI: 10.1039/d1na00110h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 04/08/2021] [Indexed: 06/14/2023]
Abstract
Flexible magneto-resistive heterostructures have received a great deal of attention over the past few years as they allow for new product paradigms that are not possible with conventional rigid substrates. While the progress and development of systems with longitudinal magnetic anisotropy on non-planar substrates has been remarkable, flexible magneto-resistive heterostructures with perpendicular magnetic anisotropy (PMA) have never been studied despite the possibility to obtain additional functionality and improved performance. To fill this gap, flexible PMA Co/Pd-based giant magneto-resistive (GMR) spin-valve stacks were prepared by using an innovative transfer-and-bonding strategy exploiting the low adhesion of a gold underlayer to SiO x /Si(100) substrates. The approach allows overcoming the limits of the direct deposition on commonly used polymer substrates, whose high surface roughness and low melting temperature could hinder the growth of complex heterostructures with perpendicular magnetic anisotropy. The obtained PMA flexible spin-valves show a sizeable GMR ratio (∼1.5%), which is not affected by the transfer process, and a high robustness against bending as indicated by the slight change of the magneto-resistive properties upon bending, thus allowing for their integration on curved surfaces and the development of a novel class of advanced devices based on flexible magneto-resistive structures with perpendicular magnetic anisotropy. Besides endowing the family of flexible electronics with PMA magneto-resistive heterostructures, the exploitation of the results might apply to high temperature growth processes and to the fabrication of other functional and flexible multilayer materials engineered at the nanoscale.
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Affiliation(s)
- M Hassan
- Consiglio Nazionale delle Ricerche, Istituto di Struttura della Materia, nM2-Lab Via Salaria km 29.300 Monterotondo Scalo (Roma) 00015 Italy
- Università Politecnica delle Marche, Dipartimento SIMAU Via Brecce Bianche Ancona 60131 Italy
| | - S Laureti
- Consiglio Nazionale delle Ricerche, Istituto di Struttura della Materia, nM2-Lab Via Salaria km 29.300 Monterotondo Scalo (Roma) 00015 Italy
| | - C Rinaldi
- Politecnico di Milano, Department of Physics and IFN-CNR via G. Colombo 81 20133 Milano Italy
| | - F Fagiani
- Politecnico di Milano, Department of Physics and IFN-CNR via G. Colombo 81 20133 Milano Italy
| | - S Varotto
- Politecnico di Milano, Department of Physics and IFN-CNR via G. Colombo 81 20133 Milano Italy
| | - G Barucca
- Università Politecnica delle Marche, Dipartimento SIMAU Via Brecce Bianche Ancona 60131 Italy
| | - N Y Schmidt
- University of Augsburg, Institute of Physics Universitätsstraße 1 Nord D-86159 Augsburg Germany
| | - G Varvaro
- Consiglio Nazionale delle Ricerche, Istituto di Struttura della Materia, nM2-Lab Via Salaria km 29.300 Monterotondo Scalo (Roma) 00015 Italy
| | - M Albrecht
- University of Augsburg, Institute of Physics Universitätsstraße 1 Nord D-86159 Augsburg Germany
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Lee S, Ryu J, Park BG. Magnetization switching through symmetry. NATURE NANOTECHNOLOGY 2021; 16:227-228. [PMID: 33712735 DOI: 10.1038/s41565-021-00850-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Affiliation(s)
- Soogil Lee
- Department of Materials Science and Engineering, KAIST, Daejeon, Korea
| | - Jeongchun Ryu
- Department of Materials Science and Engineering, KAIST, Daejeon, Korea
| | - Byong-Guk Park
- Department of Materials Science and Engineering, KAIST, Daejeon, Korea.
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Kim JM, Kim DJ, Cheon CY, Moon KW, Kim C, Cao Van P, Jeong JR, Hwang C, Lee KJ, Park BG. Observation of Thermal Spin-Orbit Torque in W/CoFeB/MgO Structures. NANO LETTERS 2020; 20:7803-7810. [PMID: 33054243 DOI: 10.1021/acs.nanolett.0c01702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Coupling of spin and heat currents enables the spin Nernst effect, the thermal generation of spin currents in nonmagnets that have strong spin-orbit interaction. Analogous to the spin Hall effect that electrically generates spin currents and associated electrical spin-orbit torques (SOTs), the spin Nernst effect can exert thermal SOTs on an adjacent magnetic layer and control the magnetization direction. Here, the thermal SOT caused by the spin Nernst effect is experimentally demonstrated in W/CoFeB/MgO structures. It is found that an in-plane temperature gradient across the sample generates a magnetic torque and modulates the switching field of the perpendicularly magnetized CoFeB. The W thickness dependence suggests that the torque originates mainly from thermal spin currents induced in W. Moreover, the thermal SOT reduces the critical current for SOT-induced magnetization switching, demonstrating that it can be utilized to control the magnetization in spintronic devices.
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Affiliation(s)
- Jeong-Mok Kim
- Department of Materials Science and Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Dong-Jun Kim
- Department of Materials Science and Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Cheol-Yeon Cheon
- Department of Materials Science and Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Kyoung-Woong Moon
- Center for Nanometrology, Korea Research Institute of Standards and Science 267 Gajung-ro, Yuseong-gu, Daejeon, Korea, 34113, Republic of Korea
| | - Changsoo Kim
- Center for Nanometrology, Korea Research Institute of Standards and Science 267 Gajung-ro, Yuseong-gu, Daejeon, Korea, 34113, Republic of Korea
| | - Phuoc Cao Van
- Department of Materials Science and Engineering, Graduate School of Energy Science and Technology, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Jong-Ryul Jeong
- Department of Materials Science and Engineering, Graduate School of Energy Science and Technology, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Chanyong Hwang
- Center for Nanometrology, Korea Research Institute of Standards and Science 267 Gajung-ro, Yuseong-gu, Daejeon, Korea, 34113, Republic of Korea
| | - Kyung-Jin Lee
- Department of Materials Science and Engineering, Korea University KU-KIST Graduate School of Converging Science and Technology, Korea University 145 Anam-ro, Anam-dong, Seongbuk-gu, Seoul, Korea, 02841, Republic of Korea
- Department of Physics, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, 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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