Article
Nanoscience & Nanotechnology
Apu Kumar Jana, S. Narayana Jammalamadaka
Summary: In this study, we propose that the spin transfer torque mechanism can be used to shift the magnetization loop along the magnetic field axis in an infinitely long ferromagnetic nanowire without an antiferromagnetic layer. We call this phenomenon spin transfer torque bias. The occurrence of spin transfer torque bias depends on the angle between the spin-polarized current and the Zeeman field, and is attributed to the helical motion of the domain wall.
Article
Physics, Applied
Xingfeng Zhou, Zizhao Pan, Fusheng Ma
Summary: In this study, we propose and numerically demonstrate a domain wall based spin torque nano-oscillator in Z-type magnetic nanowires with perpendicular magnetic anisotropy by micromagnetic simulations. The dynamics of domain walls at Z-junctions are highly affected by the dimension of Z-junctions and current density. Three kinds of behaviors are observed, including damped oscillation, steady oscillation, and collapse. The steady oscillation can be used as spin torque nano-oscillators with a working frequency of up to 20 GHz, thus enriching the investigation of spin torque nano-oscillators at high frequencies for novel microwave emitters.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Durgesh Kumar, Hong Jing Chung, JianPeng Chan, Tianli Jin, Sze Ter Lim, Stuart S. P. Parkin, Rachid Sbiaa, S. N. Piramanayagam
Summary: Neuromorphic computing is a potential technology for low power intelligent devices. Spintronics-based neurons and synapses have higher endurance. By engineering the beta-W spin-orbit coupling material, we achieved low energy domain wall motion. The energy consumption for moving the domain wall is 27 aJ/bit, showing the potential for ultralow energy spin-based neuromorphic elements.
Article
Chemistry, Multidisciplinary
Durgesh Kumar, Hong Jing Chung, JianPeng Chan, Tianli Jin, Sze Ter Lim, Stuart S. P. Parkin, Rachid Sbiaa, S. N. Piramanayagam
Summary: Neuromorphic computing is a potential technology for low-power intelligent devices. Spintronics-based neurons and synapses have higher endurance, but low-energy domain wall devices are preferred for low-power devices. By engineering the beta-W spin-orbit coupling material, we achieve low-current density DW motion with ultralow energy consumption and current density reduction.
Article
Physics, Multidisciplinary
Guangjian Gong, Yu Wang, Jingguo Hu
Summary: The track memory based on current driven magnetic domain wall motion is a potential device for the next generation of magnetic information storage. By investigating the physical mechanisms of spin wave assisting current driven domain wall motion, it has been found that the spin wave assistance can enhance or weaken the movement depending on the driving current and spin wave parameters.
Article
Physics, Fluids & Plasmas
M. H. Jin, L. Xiong, N. J. Zhou, B. Zheng, T. J. Zhou
Summary: By numerically simulating the creep motion of a magnetic domain wall driven by electric current, we accurately determined the creep exponent and roughness exponent from scaling behaviors, finding that the adiabatic and nonadiabatic spin-transfer torques belong to different universality classes and exhibit different scaling relations. Our results are in line with experimental data, but surpass existing theoretical predictions, revealing the impact of disorder-induced pinning effect on altering the universality class of creep motion.
Article
Chemistry, Multidisciplinary
Hyun-Joong Kim, Soong-Geun Je, Kyoung-Woong Moon, Won-Chang Choi, Seungmo Yang, Changsoo Kim, Bao Xuan Tran, Chanyong Hwang, Jung-Il Hong
Summary: Research has shown the programmable exchange-coupled DW motion in antiferromagnet/ferromagnet system, where the role of an external in-plane field is replaced by the exchange bias field from the antiferromagnetic layer, enabling external field-free modulations of DW motions. Furthermore, the direction of the exchange bias field can be reconfigured by simply injecting spin currents through the device, enabling electrical and programmable operations of the device.
Article
Materials Science, Multidisciplinary
Wai Lum William Mah, Durgesh Kumar, Tianli Jin, S. N. Piramanayagam
Summary: Artificial intelligence (AI) has gained attention recently, with brain-inspired neuromorphic computing (NC) being favored for its energy efficiency. Research has focused more on artificial synapses rather than neurons due to the challenge in replicating leaky integrate-and-fire (LIF) properties.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Ya-Ru Wang, Chao Yang, Zheng-Chuan Wang, Gang Su
Summary: In this study, the generalized analytical expressions of thermal spin current and thermal spin transfer torque (TSTT) are derived based on the spinor Boltzmann equation under the local equilibrium approximation. The different terms and theoretically determinable phenomenological coefficients of the TSTT were analyzed. The Landau-Lifshitz-Gilbert-Levy equation was then solved to investigate the influence of TSTT on domain wall motion, revealing that increasing temperature and temperature gradient can enhance the velocity of domain walls.
Article
Chemistry, Multidisciplinary
Huajun Qin, Rouven Dreyer, Georg Woltersdorf, Tomoyasu Taniyama, Sebastiaan van Dijken
Summary: In multiferroic heterostructures, electric-field manipulation of spin waves has been demonstrated, showing the potential for controlling the amplitude and phase of spin waves. The electric-field effects are mediated by strain coupling between alternating ferroelectric stripe domains, leading to reversible motion of ferroelectric domain walls and pinned anisotropy boundaries that turn the spin-wave signal on and off. Additionally, linear electric-field tuning of the spin-wave phase by altering the width of the coupled stripe domains has been achieved, providing a new route towards energy-efficient reconfigurable magnonics.
ADVANCED MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Hao Zhao, Run Cheng, Quan-Hui Liu
Summary: This study presents a theoretical investigation and numerical simulations of the dynamics of domain walls in a curved nanowire with torsion in an antiferromagnetic environment. The equations of motion for the antiferromagnetic domain wall are derived, revealing that the curvature induces the Dzyaloshinskii-Moriya interaction and the torsion induces an anisotropy term, both of which drive the domain wall in opposite directions in a stable state.
RESULTS IN PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Qiuyuan Wang, Yi Zeng, Kai Yuan, Qingqi Zeng, Pingfan Gu, Xiaolong Xu, Hanwen Wang, Zheng Han, Kentaro Nomura, Wenhong Wang, Enke Liu, Yanglong Hou, Yu Ye
Summary: The efficiency of spintronic devices can be improved by generating higher effective magnetic fields with lower working currents. Spin-transfer torques can drive magnetic domain wall motion in a device composed of a single material. Here, we report magnetism modulation in Co3Sn2S2-a magnetic Weyl semimetal-via spin-transfer-torque-driven domain wall motion. The threshold current density for driving domain wall motion is less than 5.1 x 10(5) A cm(-2) at zero external field and less than 1.5 x 10(5) A cm(-2) at a moderate external field (0.2 kOe). The spin-transfer-torque effective field can reach as high as 2.4-5.6 kOe MA(-1) cm(2) at 150 K.
NATURE ELECTRONICS
(2023)
Article
Physics, Applied
Xiangjun Xing, T. Wang, Yan Zhou
Summary: Traveling spin waves in magnonic waveguides undergo severe attenuation, but utilizing a ferromagnet/heavy metal bilayer can efficiently control the decay of spin waves, enriching the toolset for magnonic technologies.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Conor J. McCluskey, Matthew G. Colbear, James P. McConville, Shane J. McCartan, Jesi R. Maguire, Michele Conroy, Kalani Moore, Alan Harvey, Felix Trier, Ursel Bangert, Alexei Gruverman, Manuel Bibes, Amit Kumar, Raymond G. P. McQuaid, J. Marty Gregg
Summary: Recent research has revealed the presence of magnetoresistance in domain walls, providing insight into the conduction properties of homointerfaces.
ADVANCED MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Xue Liang, Zhenyu Wang, Peng Yan, Yan Zhou
Summary: In this study, we theoretically investigate the propagation of spin waves in a Neel-type ferrimagnetic domain-wall channel in the presence of interfacial Dzyaloshinskii-Moriya interaction (DMI). We observe a nonreciprocal spin-wave propagation induced by the antisymmetric chiral DMI, which can be controlled by changing the net angular momentum or the polarity of domain walls. By applying three-magnon processes, we are able to nonlinearly detect and quantify the bounded mode in the narrow channel, and determine the frequency, wave vector, and DMI strength. These findings have significant implications for fabricating energy-efficient magnetic devices and measuring interfacial DMI in ultra-narrow ferrimagnetic stripes.
Article
Physics, Applied
K. Saito, A. Imai, S. Ota, T. Koyama, A. Ando, D. Chiba
Summary: This study demonstrates the considerable potential of a CoFeB/MgO-based magnetic tunnel junction (MTJ) directly formed on a flexible substrate as a high-sensitivity strain gauge. Under the condition of external magnetic-field assistance, the flexible MTJ achieves a gauge factor of approximately 1000, which is the highest sensitivity reported for a film-type strain gauge and about 500 times larger than that of the most prevalent metal-foil strain gauge. Moreover, using a flexible MTJ with strain-insensitive and strain-sensitive layers, a large resistance change due to strain application can be achieved even without the presence of a magnetic field.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Yutaro Takeuchi, Ryotaro Okuda, Junta Igarashi, Butsurin Jinnai, Takaharu Saino, Shoji Ikeda, Shunsuke Fukami, Hideo Ohno
Summary: In this study, a thin-film deposition technique for a-few-nanometer-thin L1(0)-MnAl was developed and its structure and magnetic properties were investigated. The results show that L1(0)-MnAl has a large crystalline anisotropy and small spontaneous magnetization, making it a promising material for high-density and high-speed STT-MRAM.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
T. Koyama, Y. Nakatani, D. Chiba
Summary: In this study, a Pt/Co/MgO system with regions exhibiting different anisotropy was artificially created to investigate the chirality-induced EMF at the PM/IM boundary. The EMF in the IM region was probed using magnetoresistance measurements, revealing that it predominantly acts on the magnetization near the PM/IM boundary. The sign and magnitude of the observed EMF suggest that it is caused by iDMI in the present system.
APPLIED PHYSICS LETTERS
(2022)
Review
Physics, Multidisciplinary
Durgesh Kumar, Tianli Jin, Rachid Sbiaa, Mathias Klaui, Subhankar Bedanta, Shunsuke Fukami, Dafine Ravelosona, See-Hun Yang, Xiaoxi Liu, S. N. Piramanayagam
Summary: Digital data generated by corporate and individual users is growing due to the use of digital applications. While flash memory devices are replacing HDDs in certain applications, HDDs still dominate the storage of digital data in cloud and servers. Domain wall memory (DWM) is a potential alternative to HDDs, offering lower power consumption and higher storage capacity. However, there are challenges to be addressed before DWM can become commercially viable.
PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS
(2022)
Article
Physics, Applied
Hiroto Masuda, Takeshi Seki, Yuta Yamane, Rajkumar Modak, Ken-ichi Uchida, Jun'ichi Ieda, Yong-Chang Lau, Shunsuke Fukami, Koki Takanashi
Summary: This paper investigates the role of antisymmetric interlayer exchange coupling (AIEC) in the magnetization switching of a synthetic antiferromagnet and identifies key factors through experimental and theoretical analysis. The results demonstrate that perpendicular magnetization switching can be achieved solely by applying an in-plane magnetic field.
PHYSICAL REVIEW APPLIED
(2022)
Article
Physics, Applied
Sosuke Hori, Kohei Ueda, Takanori Kida, Masayuki Hagiwara, Jobu Matsuno
Summary: We report on the highly efficient spin-orbit torque generation in epitaxial SrIrO3. By measuring the CoFeB/SIO bilayers, we find that the dampinglike SOT is much larger than the fieldlike SOT. Compared with the Pt control sample, the observed efficiency of SIO for dampinglike SOT is three times higher and almost independent of the CoFeB thickness. These results highlight the potential of epitaxial SIO for low-current and reliable spin-orbit torque-controlled devices.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Rajeswari Roy Chowdhury, Samik DuttaGupta, Chandan Patra, Anshu Kataria, Shunsuke Fukami, Ravi Prakash Singh
Summary: This study explores the magnetoresistive properties of the spin-ladder antiferromagnetic material TaFe1.25Te3, revealing an unusual anharmonic behavior and anisotropic enhancement. These results are important for our understanding of the magnetoresistive properties of low-dimensional layered antiferromagnets and the potential use of these materials for antiferromagnetic spintronics.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Physics, Applied
Kenta Fukushima, Kohei Ueda, Naoki Moriuchi, Takanori Kida, Masayuki Hagiwara, Jobu Matsuno
Summary: We studied spin Hall magnetoresistance (SMR) in Pt/ferrimagnetic insulator Y3Fe5O12 (YIG) bilayers and found that large SMR can be achieved regardless of the crystallinity. The optimized Pt/YIG showed high interface quality and spin current performance. SMR correlated with magnetization, interface roughness, and carrier density.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Keito Kobayashi, Keisuke Hayakawa, Junta Igarashi, William A. Borders, Shun Kanai, Hideo Ohno, Shunsuke Fukami
Summary: By fabricating stochastic magnetic tunnel junctions with synthetic antiferromagnetic free layers, this research demonstrates their robust relaxation times against external magnetic fields, providing design guidelines for stochastic MTJs targeting probabilistic computers.
PHYSICAL REVIEW APPLIED
(2022)
Article
Physics, Applied
Yuma Sato, Yutaro Takeuchi, Yuta Yamane, Ju-Young Yoon, Shun Kanai, Jun'ichi Ieda, Hideo Ohno, Shunsuke Fukami
Summary: The thermal stability of antiferromagnetic Mn3Sn nanodots was studied, and the results showed that the thermal stability factor decreases when the diameter is smaller than 300 nm. These findings provide a basis for understanding the thermal fluctuation and reversal mechanism of antiferromagnets for device applications.
APPLIED PHYSICS LETTERS
(2023)
Review
Chemistry, Physical
Jiahao Han, Ran Cheng, Luqiao Liu, Hideo Ohno, Shunsuke Fukami
Summary: Antiferromagnets have attracted extensive interest in spintronics and various applications have been developed based on the coherent effects of antiferromagnet dynamics. This Review categorizes and analyzes the critical effects, including spin pumping, spin transmission, electrically induced spin rotation and ultrafast spin-orbit effects, that harness the coherence of antiferromagnets for spintronic applications. Future opportunities in research and applications in coherent antiferromagnetic spintronics are also discussed.
Article
Nanoscience & Nanotechnology
Kohei Ueda, Hayato Fujii, Takanori Kida, Masayuki Hagiwara, Jobu Matsuno
Summary: We report on the generation of efficient spin current in rutile-type WO2 at room temperature. The WO2 film is characterized by its metallic conductivity and monoclinically distorted rutile structure. By conducting measurements, we find that the dampinglike spin-orbit torque (SOT) in WO2 is larger than the fieldlike one, and the efficiency of WO2 is about two-thirds of that of W. The positive sign of the dampinglike SOT in WO2 can be explained by preceding theoretical studies.
Article
Computer Science, Hardware & Architecture
Shuvro Chowdhury, Andrea Grimaldi, Navid Anjum Aadit, Shaila Niazi, Masoud Mohseni, Shun Kanai, Hideo Ohno, Shunsuke Fukami, Luke Theogarajan, Giovanni Finocchio, Supriyo Datta, Kerem Y. Camsari
Summary: The transistor turned 75 in 2022 and continues to scale, albeit at a slower pace dictated by Moore's law. In the face of increasing computing demands and energy consumption of modern AI algorithms, integrating transistors with unconventional technologies has become a promising approach for domain-specific computing.
IEEE JOURNAL ON EXPLORATORY SOLID-STATE COMPUTATIONAL DEVICES AND CIRCUITS
(2023)
Article
Physics, Applied
Ryuji Atsumi, Junichi Shiogai, Takumi Yamazaki, Takeshi Seki, Kohei Ueda, Jobu Matsuno
Summary: Manganite perovskites have emerging physical properties of strongly-correlated electrons, and using the epitaxial lift-off technique can enhance the saturation magnetization and ferromagnetic transition temperature. They are suitable for flexible electronic applications.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Motoya Shinozaki, Junta Igarashi, Shuichi Iwakiri, Takahito Kitada, Keisuke Hayakawa, Butsurin Jinnai, Tomohiro Otsuka, Shunsuke Fukami, Kensuke Kobayashi, Hideo Ohno
Summary: Magnetic tunnel junctions (MTJs) with spin-dependent conductance were investigated in this study. The nonlinear conductance at low bias regime was evaluated in nanoscale MTJs. The relationships between different conductance components were examined. The results indicated that the conductance components were correlated with the junction size and external magnetic field. The findings provide insights into the electron transport mechanism in nanoscale MTJs.
