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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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Hadámek T, Jørstad NP, de Orio RL, Goes W, Selberherr S, Sverdlov V. A Comprehensive Study of Temperature and Its Effects in SOT-MRAM Devices. MICROMACHINES 2023; 14:1581. [PMID: 37630117 PMCID: PMC10456936 DOI: 10.3390/mi14081581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 07/30/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023]
Abstract
We employ a fully three-dimensional model coupling magnetization, charge, spin, and temperature dynamics to study temperature effects in spin-orbit torque (SOT) magnetoresistive random access memory (MRAM). SOTs are included by considering spin currents generated through the spin Hall effect. We scale the magnetization parameters with the temperature. Numerical experiments show several time scales for temperature dynamics. The relatively slow temperature increase, after a rapid initial temperature rise, introduces an incubation time to the switching. Such a behavior cannot be reproduced with a constant temperature model. Furthermore, the critical SOT switching voltage is significantly reduced by the increased temperature. We demonstrate this phenomenon for switching of field-free SOT-MRAM. In addition, with an external-field-assisted switching, the critical SOT voltage shows a parabolic decrease with respect to the voltage applied across the magnetic tunnel junction (MTJ) of the SOT-MRAM cell, in agreement with recent experimental data.
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Affiliation(s)
- Tomáš Hadámek
- Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Institute for Microelectronics, TU Wien, Gußhausstraße 27-29, A-1040 Wien, Austria (V.S.)
| | - Nils Petter Jørstad
- Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Institute for Microelectronics, TU Wien, Gußhausstraße 27-29, A-1040 Wien, Austria (V.S.)
| | | | | | - Siegfried Selberherr
- Institute for Microelectronics, TU Wien, Gußhausstraße 27-29, A-1040 Wien, Austria
| | - Viktor Sverdlov
- Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Institute for Microelectronics, TU Wien, Gußhausstraße 27-29, A-1040 Wien, Austria (V.S.)
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Magnetisation switching dynamics induced by combination of spin transfer torque and spin orbit torque. Sci Rep 2022; 12:3380. [PMID: 35233036 PMCID: PMC8888771 DOI: 10.1038/s41598-022-07277-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 02/15/2022] [Indexed: 11/09/2022] Open
Abstract
We present a theoretical investigation of the magnetisation reversal process in CoFeB-based magnetic tunnel junctions (MTJs). We perform atomistic spin simulations of magnetisation dynamics induced by combination of spin orbit torque (SOT) and spin transfer torque (STT). Within the model the effect of SOT is introduced as a Slonczewski formalism, whereas the effect of STT is included via a spin accumulation model. We investigate a system of CoFeB/MgO/CoFeB coupled with a heavy metal layer where the charge current is injected into the plane of the heavy metal meanwhile the other charge current flows perpendicular into the MTJ structure. Our results reveal that SOT can assist the precessional switching induced by spin polarised current within a certain range of injected current densities yielding an efficient and fast reversal on the sub-nanosecond timescale. The combination of STT and SOT gives a promising pathway to improve high performance CoFeB-based devices with high speed and low power consumption.
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Kang DH, Shin M. Critical switching current density of magnetic tunnel junction with shape perpendicular magnetic anisotropy through the combination of spin-transfer and spin-orbit torques. Sci Rep 2021; 11:22842. [PMID: 34819554 PMCID: PMC8613283 DOI: 10.1038/s41598-021-02185-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 11/08/2021] [Indexed: 11/17/2022] Open
Abstract
Recently, magnetic tunnel junctions (MTJs) with shape perpendicular magnetic anisotropy (S-PMA) have been studied extensively because they ensure high thermal stability at junctions smaller than 20 nm. Furthermore, spin-transfer torque (STT) and spin-orbit torque (SOT) hybrid switching, which guarantees fast magnetization switching and deterministic switching, has recently been achieved in experiments. In this study, the critical switching current density of the MTJ with S-PMA through the interplay of STT and SOT was investigated using theoretical and numerical methods. As the current density inducing SOT ([Formula: see text]) increases, the critical switching current density inducing STT ([Formula: see text]) decreases. Furthermore, for a given [Formula: see text], [Formula: see text] increases with increasing thickness, whereas [Formula: see text] decreases as the diameter increases. Moreover, [Formula: see text] in the plane of thickness and spin-orbit field-like torque ([Formula: see text]) was investigated for a fixed [Formula: see text] and diameter. Although [Formula: see text] decreases with increasing [Formula: see text], [Formula: see text] slowly increases with increasing thickness and increasing [Formula: see text]. The power consumption was investigated as a function of thickness and diameter at the critical switching current density. Experimental confirmation of these results using existing experimental techniques is anticipated.
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Affiliation(s)
- Doo Hyung Kang
- grid.37172.300000 0001 2292 0500School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141 South Korea
| | - Mincheol Shin
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea.
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Li K, Feng J, Yuan X, Gan L, Lu Z, Xiong R. Study on a new manner of the magnetization switching actuated by a unidirectional pulse current. NANOTECHNOLOGY 2021; 33:025001. [PMID: 34614479 DOI: 10.1088/1361-6528/ac2d48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
A new writing scheme with a unidirectional pulse current is proposed for spin transfer torque (STT) based magnetic random-access memory (MRAM). To investigate the feasibility of the writing scheme, bilayered nano-pillars composed of a soft layer with small in-plane shape anisotropy and a hard layer with either large perpendicular anisotropy (PMA) or in-plane anisotropy (IMA) are designed and their switching behaviors are studied. It is found that in either type of bilayered nano-pillars, with the aid of the attached hard layer, the magnetization of the soft layer can be switched back and forth under a unidirectional pulse current. In an IMA/IMA nano-pillar, the magnetization of the free layer (FL) can achieve excellent alignment, which is in contrast to the IMA/PMA nano-pillar. By optimizing the dimensions and magnetic parameters of the IMA/IMA nano-pillar, a decently low switching current density (4.3 × 1011A m-2) and ultrashort switching time (<1 ns) can be reached. Based on these results, the unidirectional writing scheme is practical if an IMA/IMA bilayer is used to replace the FL in a magnetic tunnel junction. Considering that a unidirectional writing scheme can enable the application of materials with high spin polarization such as half metals, and avoid the injection of writing current into junction using a special design, it may be very promising for STT-MRAM.
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Affiliation(s)
- K Li
- The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
- School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
| | - J Feng
- The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
- School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
| | - X Yuan
- The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
- School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
| | - L Gan
- The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
- School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
| | - Z Lu
- The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
- School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People's Republic of China
| | - R Xiong
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China
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Ou QF, Xiong BS, Yu L, Wen J, Wang L, Tong Y. In-Memory Logic Operations and Neuromorphic Computing in Non-Volatile Random Access Memory. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E3532. [PMID: 32785179 PMCID: PMC7475900 DOI: 10.3390/ma13163532] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/03/2020] [Accepted: 08/06/2020] [Indexed: 02/04/2023]
Abstract
Recent progress in the development of artificial intelligence technologies, aided by deep learning algorithms, has led to an unprecedented revolution in neuromorphic circuits, bringing us ever closer to brain-like computers. However, the vast majority of advanced algorithms still have to run on conventional computers. Thus, their capacities are limited by what is known as the von-Neumann bottleneck, where the central processing unit for data computation and the main memory for data storage are separated. Emerging forms of non-volatile random access memory, such as ferroelectric random access memory, phase-change random access memory, magnetic random access memory, and resistive random access memory, are widely considered to offer the best prospect of circumventing the von-Neumann bottleneck. This is due to their ability to merge storage and computational operations, such as Boolean logic. This paper reviews the most common kinds of non-volatile random access memory and their physical principles, together with their relative pros and cons when compared with conventional CMOS-based circuits (Complementary Metal Oxide Semiconductor). Their potential application to Boolean logic computation is then considered in terms of their working mechanism, circuit design and performance metrics. The paper concludes by envisaging the prospects offered by non-volatile devices for future brain-inspired and neuromorphic computation.
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Affiliation(s)
- Qiao-Feng Ou
- School of Information Engineering, Nanchang Hangkong University, Nanchang 330063, China; (Q.-F.O.); (B.-S.X.); (L.Y.); (J.W.)
| | - Bang-Shu Xiong
- School of Information Engineering, Nanchang Hangkong University, Nanchang 330063, China; (Q.-F.O.); (B.-S.X.); (L.Y.); (J.W.)
| | - Lei Yu
- School of Information Engineering, Nanchang Hangkong University, Nanchang 330063, China; (Q.-F.O.); (B.-S.X.); (L.Y.); (J.W.)
| | - Jing Wen
- School of Information Engineering, Nanchang Hangkong University, Nanchang 330063, China; (Q.-F.O.); (B.-S.X.); (L.Y.); (J.W.)
| | - Lei Wang
- School of Information Engineering, Nanchang Hangkong University, Nanchang 330063, China; (Q.-F.O.); (B.-S.X.); (L.Y.); (J.W.)
| | - Yi Tong
- College of Electronic and Optical Engineering & College of Microelectronics, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
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