Article
Chemistry, Multidisciplinary
Jinwu Wei, Xiao Wang, Baoshan Cui, Chenyang Guo, Hongjun Xu, Yao Guang, Yuqiang Wang, Xuming Luo, Caihua Wan, Jiafeng Feng, Hongxiang Wei, Gen Yin, Xiufeng Han, Guoqiang Yu
Summary: Synthetic antiferromagnets (SAFs) show potential in next-generation spintronic devices due to zero net magnetization and high thermal stability, despite typically requiring an in-plane effective magnetic field. A new study demonstrates field-free switching in an all-SAF system with significantly reduced net magnetization, showing robustness up to approximately 460 K.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Tianli Jin, Gerard Joseph Lim, Han Yin Poh, Shuo Wu, Funan Tan, Wen Siang Lew
Summary: This study proposes a technique to modulate the spin reflection and spin density of states within a heavy-metal Pt through interfacing with a dielectric MgO layer. The researchers demonstrate tunability of the effective out-of-plane spin torque acting on the ferromagnetic Co layer, enabling current-induced SOT magnetization switching without the assistance of an external magnetic field. The influence of the MgO layer thickness on effective SOT efficiency shows saturation at 4 nm, while up to 80% of field-free magnetization switching ratio is achieved with the MgO between 5 and 8 nm. By substituting the dielectric with Ti or Pt, the researchers confirm that the MgO layer is indeed responsible for the observed field-free magnetization switching mechanism.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Lizhu Ren, Liang Liu, Xinyu Shu, Weinan Lin, Ping Yang, Jingsheng Chen, Kie Leong Teo
Summary: The experimental demonstration of current-induced spin-orbit torque (SOT) magnetization switching in a ferrimagnetic D0(22)-Mn3Ge film with high bulk PMA and thermal stability suggests it as a promising candidate for high-density SOT magnetic random-access memory devices. The large effective damping-like SOT efficiency and magnetization switching can be explained by the double-spin source layers and negative-exchange interaction of the ferrimagnet.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Physics, Applied
Xupeng Zhao, Siwei Mao, Hailong Wang, Dahai Wei, Jianhua Zhao
Summary: This study reports spin-orbit torque-induced magnetization switching in L1(0)-MnGa/FeMn/Pt trilayers, utilizing an antiferromagnetic FeMn layer to achieve field-free spin-orbit torque switching. The research found that the spin transmission efficiency decreases monotonically with increasing FeMn thickness, with a peak in the damping-like spin-orbit torque efficiency at 1.5nm FeMn thickness. These results demonstrate the effectiveness of emerging spintronic devices containing antiferromagnetic elements.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Lizhu Ren, Chenghang Zhou, Xiaohe Song, Herng Tun Seng, Liang Liu, Chaojiang Li, Tieyang Zhao, Zhenyi Zheng, Jun Ding, Yuan Ping Feng, Jingsheng Chen, Kie Leong Teo
Summary: Electrically manipulating magnetic moments by spin-orbit torque (SOT) has potential applications in magnetic memories and logic devices. In this study, highly textured, polycrystalline Heusler alloy MnxPtyGe (MPG) films were found to exhibit reversible switching of magnetization with low switching current density. Additionally, MPG shows a memristive characteristic and the ability for deterministic field-free switching of magnetization.
Article
Materials Science, Multidisciplinary
Man Yang, Bingfeng Miao, Jun Cheng, Kang He, Xi Yang, Yulun Zeng, Ziqiang Wang, Liang Sun, Xiangrong Wang, Antonio Azevedo, Subhankar Bedanta, Haifeng Ding
Summary: This study reports spin-charge conversion in perpendicular magnetized Co/Pd multilayers, observing the anomalous inverse spin Hall effect (AISHE) and finding that the sign and magnitude of AISHE can be regulated by the magnetization of the multilayers.
Article
Chemistry, Physical
I-Hsuan Kao, Ryan Muzzio, Hantao Zhang, Menglin Zhu, Jacob Gobbo, Sean Yuan, Daniel Weber, Rahul Rao, Jiahan Li, James H. Edgar, Joshua E. Goldberger, Jiaqiang Yan, David G. Mandrus, Jinwoo Hwang, Ran Cheng, Jyoti Katoch, Simranjeet Singh
Summary: This paper demonstrates the experimental realization of field-free deterministic magnetic switching using the out-of-plane antidamping spin-orbit torque in the quantum material WTe2, and confirms this phenomenon through numerical simulations. This is of great importance for next-generation spintronic applications.
Article
Physics, Applied
Tuo Fan, Nguyen Huynh Duy Khang, Takanori Shirokura, Ho Hoang Huy, Pham Nam Hai
Summary: The study demonstrates that sputtered BiSb topological insulators in Pt/Co/Pt-MgO heterostructures have high effective spin Hall angle and electrical conductivity, allowing for magnetization switching at low current densities. This highlights the high efficiency and robustness of BiSb as a spin current source in realistic SOT-MRAM applications.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Weihao Li, Wenkai Zhu, Gaojie Zhang, Hao Wu, Shouguo Zhu, Runze Li, Enze Zhang, Xiaomin Zhang, Yongcheng Deng, Jing Zhang, Lixia Zhao, Haixin Chang, Kaiyou Wang
Summary: In this study, the perpendicular magnetization of the vdW ferromagnet Fe3GaTe2 was successfully switched at room temperature using spin-orbit torques with a relatively low current density. The high efficiency of this method, quantitatively determined by harmonic measurements, provides a significant basis for the development of vdW-ferromagnet-based spintronic applications.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
Huanglin Yang, Shuai Hu, Meng Tang, Shiwei Chen, Huanjian Chen, Di Wu, Xuepeng Qiu
Summary: In the study of perpendicularly magnetized [Ni-Co](2)/Ir heterostructures, it is found that Ir's low resistivity allows for less power consumption in spin-orbit torque-driven magnetization switching compared to Pt or Ta-based devices. Additionally, the Dzyaloshinskii-Moriya interaction field and coefficient at the [Ni-Co](2)/Ir interface are determined, suggesting Ir as a beneficial material for ultralow-power and high-density spin-orbit torque memory and logic devices.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Multidisciplinary
Ying Cao, Zhicheng Xie, Zhiyuan Zhao, Yumin Yang, Na Lei, Bingfeng Miao, Dahai Wei
Summary: This paper investigates the performance of spin-orbit torque in heavy metal/ferromagnetic metal periodic multilayers. A series of perpendicular magnetized multilayers were successfully fabricated and the thickness of the Ni layer was varied to study the spin-orbit torque. The efficiency of the spin-orbit torque was found to be effectively modulated by the ratio of Pt and Ni in the multilayers.
Article
Nanoscience & Nanotechnology
Min Wang, Zhaohao Wang, Chao Wang, Weisheng Zhao
Summary: This research proposes a novel field-free deterministic magnetization switching scheme by using two currents sequentially passing interlaced paths in a regular magnetic tunnel junction. The switching is bipolar since the final magnetization state depends on the combination of current paths. The functionality and robustness of the proposed scheme are validated through both macrospin and micromagnetic simulation.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Physics, Applied
Zhuoyi Li, Xianyang Lu, Zhe Zhang, Wenjia Li, TaoTao Li, Jian Zhou, Yu Yan, Ruobai Liu, Jun Du, Ronghua Liu, Xinran Wang, Yao Li, Liang He, Jing Wu, Rong Zhang, Yongbing Xu
Summary: This study conducted a comprehensive investigation on improving the spin-orbit torque (SOT) efficiency of the Ta/CoFeB structure by inserting an oxide insulating layer Fe2O3. It was found that a thickness of only 1-5 nm of Fe2O3 significantly reduced the SOT critical switching current by 70% and enhanced the spin Hall angle of Ta. Both types of spin-orbit torques, damping-like and field-like torques, were significantly enhanced. The observed enhanced SOT efficiency was attributed to the atomic diffusion of O from the Fe2O3 underlayer, leading to the partial oxidization of the Ta layer and the Ta/CoFeB interfaces. The results provide a reliable method to improve the SOT performance in perpendicularly magnetized structures for potential real-world applications in spintronic devices.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Lijun Zhu, D. C. Ralph, R. A. Buhrman
Summary: Research shows that there is no simple correlation between the efficiency of dampinglike spin orbit torque and the critical switching current density of perpendicularly magnetized spin-current generator-ferromagnet heterostructures, especially in micrometer-sized samples. The values of efficiency based on switching current densities can sometimes severely underestimate or overestimate the actual efficiency, making critical switching current densities alone a poor predictor of the relative strength of spin-current generators.
PHYSICAL REVIEW APPLIED
(2021)
Article
Nanoscience & Nanotechnology
Fen Xue, Shy-Jay Lin, Peng Li, William Hwang, Yen-Lin Huang, Wilman Tsai, Shan X. Wang
Summary: In this study, significant changes in spin-orbit torques (SOTs) were observed in Pt/Co/Mg/CoFeB heterostructures after inserting a thin Co film. The damping-like effective field was enhanced while the field-like effective field was reduced to near zero value by inserting a thin Co layer with weak perpendicular magnetic anisotropy (PMA). Dynamic spin pumping coupling between Pt/Co with weak PMA and in-plane CoFeB could modulate the effective SOTs in the heterostructure, depending on the thickness of the spacer Mg.
Article
Nanoscience & Nanotechnology
Yao Guang, Like Zhang, Junwei Zhang, Yadong Wang, Yuelei Zhao, Riccardo Tomasello, Senfu Zhang, Bin He, Jiahui Li, Yizhou Liu, Jiafeng Feng, Hongxiang Wei, Mario Carpentieri, Zhipeng Hou, Junming Liu, Yong Peng, Zhongming Zeng, Giovanni Finocchio, Xixiang Zhang, John Michael David Coey, Xiufeng Han, Guoqiang Yu
Summary: Magnetic skyrmions are a promising information carrier for dense and energy-efficient information storage. This study reports a method to achieve skyrmions in a magnetic tunnel junction (MTJ) through magnetostatic interactions and successfully identifies the electrical response of a single skyrmion through electrical measurements. This is an important step towards the all-electric detection of skyrmions.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Leyi Li, Enkui Yi, Bin Wang, Guoqiang Yu, Bing Shen, Zhongbo Yan, Meng Wang
Summary: In this work, unconventional prominent planar Hall effect (PHE) and planar anisotropic magnetoresistivity (PAMR) were observed in strange kagome metal KV3Sb5. These effects, which are driven by an in-plane magnetic field and display sharp difference from other Hall effects driven by an out-of-plane magnetic field or magnetization, exhibit exotic higher-order oscillations in sharp contrast to those following empirical rule only allowing two-fold symmetrical oscillations. These higher-order oscillations exhibit strong field and temperature dependence and vanish around charge density wave (CDW) transition, suggesting a significant interplay of the lattice, magnetic and electronic structure in KV3Sb5.
NPJ QUANTUM MATERIALS
(2023)
Article
Physics, Applied
C. Cheng, Z. R. Yan, Y. W. Xing, J. Dong, Y. Zhang, C. H. Wan, G. Q. Yu, Z. C. Xia, L. Li, X. F. Han
Summary: The dispersion relationships in antiferromagnetically coupled magnonic crystals (MCs) were investigated using micromagnetic simulations. Unlike traditional MCs, antiferromagnetically coupled MCs have two oppositely polarized modes, allowing the realization of synthetic ferrimagnetic and synthetic antiferromagnetic MCs. The study discovered the magnon flatband effect and achieved a large bandgap in the dispersion relation. The study also proposed spin-wave filtering devices based on the influence of thickness and thickness ratio on the dispersion bands' center frequency and width. The research provides fresh insights into the development of ultra-efficient magnonic devices.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Jing Dong, Chen Cheng, Jinwu Wei, Hongjun Xu, Yu Zhang, Yuqiang Wang, Zengwei Zhu, Liang Li, Hao Wu, Guoqiang Yu, Xiufeng Han
Summary: This work focuses on the enhancement of damping-like and field-like spin-orbit torque (SOT) efficiencies and interfacial spin transparency (T-in) in the Py/NiO/Pt heterostructure. The SOT efficiencies and T-in are characterized using the spin-torque ferromagnetic resonance (ST-FMR) and spin-pumping (SP) techniques. By extracting and subtracting the inverse spin Hall voltage contamination induced by SP, accurate SOT efficiencies and T-in are obtained. The results show that the NiO insertion layer thickness affects the damping-like and field-like SOT efficiencies, indicating the importance of T-in. The maximum T-in reaches 0.82 for a 0.6 nm-thick NiO layer. This work highlights the effectiveness of NiO insertion in enhancing T-in and SOT efficiency.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Jie Chen, Peng Chen, Tengyu Guo, Dongfeng Zheng, Hang Li, Guoqiang Yu, Yong-Chang Lau, Xuekui Xi, Wenhong Wang
Summary: We conducted detailed magnetic and anisotropic magnetoresistance (AMR) measurements on a magnetic-field-induced topological Weyl semimetal, TbPtBi, which exhibits a weak metamagnetic transition in the antiferromagnetic state. The results indicate that the spin order dominates the symmetry of AMR curves at temperatures below the Neel temperature (T-N) and low magnetic fields. As the magnetic fields increase, the AMR with a twofold symmetry gradually becomes dominant. Moreover, sign change in the AMR effect is confirmed for both T < T-N and T > T-N at high magnetic fields, which may be related to the magnetic field-induced splitting of the topological band in TbPtBi.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Mengyun He, Yu Huang, Huimin Sun, Yu Fu, Peng Zhang, Chenbo Zhao, Kang. L. L. Wang, Guoqiang Yu, Qing Lin He
Summary: By investigating the roles played by the Aharonov-Bohm effect and Coulomb interactions, we successfully constructed magnetic interferometers using Cr-doped (Bi,Sb)(2)Te-3 films and demonstrated electronic interferometry using chiral edge states in the quantum anomalous Hall regime. The observed interference patterns highlight the interplay between Coulomb interactions and Aharonov-Bohm interference by edge states. The long-range coherence and robustness against thermal smearing exhibited by the observed interference are likely due to the long-range magnetic order. Our interferometer provides a platform for (quasi)particle interference and topological qubits.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Condensed Matter
Xuming Luo, Yuqiang Wang, Shiqiang Liu, Tengyu Guo, Xiufeng Han, Guoqiang Yu
Summary: We have controlled the interlayer exchange coupling in a perpendicularly magnetized synthetic antiferromagnet by tuning the layer thickness and material composition. The spin-orbit torque driven magnetization switching behavior is influenced by the strength of the interlayer exchange coupling. When the exchange coupling is weak, the switching behavior is dominated by the external magnetic field, while for ultra-strong exchange coupling, the effective magnetic field determines the switching behavior. These findings advance the understanding of spin-orbit torque switching in perpendicular synthetic antiferromagnets and promote their applications in low stray field and low power spintronic devices.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Physics, Condensed Matter
Mengyun He, Yu Fu, Yu Huang, Huimin Sun, Tengyu Guo, Wenlu Lin, Yu Zhu, Yan Zhang, Yang Liu, Guoqiang Yu, Qing Lin He
Summary: This study investigates the effects of intrinsic and extrinsic doping on MnBi2Te4 epitaxial films and demonstrates the role of surface epitaxy in optimizing crystalline quality and defect engineering. Intrinsic antisite defects can be used to tune the Fermi level position, while extrinsic Sb doping compensates for this effect and modifies the magnetism and topology of the film, leading to a topological phase transition.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Chemistry, Multidisciplinary
Meiling Li, Chexin Li, Xiaoguang Xu, Mengxi Wang, Zhiqiang Zhu, Kangkang Meng, Bin He, Guoqiang Yu, Youfan Hu, Lian -Mao Peng, Yong Jiang
Summary: This research demonstrates a type of nonvolatile, low power dissipation, and programmable flexible spin logic device based on spin-orbit torque. The device has stable performance and the magnetization switching ratio does not change after bending 100 times. It can realize five Boolean logic gates and can be transferred to various substrates while maintaining high performance. The flexible spin logic device has applications in wearable electronics.
Article
Nanoscience & Nanotechnology
Xu Zhang, Xiaolu Wang, Qisheng Jiang, Wenqing He, Yongqiang Yang, Qianxun Gong, Tengyu Guo, Peng Chen, Jing Zhang, Guoqiang Yu, Xiufeng Han, Kang L. Wang, Yue Wang, Baoshan Cui, Hao Wu
Summary: This paper investigates current-induced magnetization switching in the ferrimagnetic Ta/GdFeCo/MgO system and finds robust spin-orbit torque (SOT)-induced magnetization switching at the magnetic compensation temperature of around 70 K, where the magnetization is nearly zero and coercivity can reach almost 3 T. The temperature dependence of SOT efficiency is characterized using the second harmonic method, and the enhanced SOT efficiency near the compensation temperature is attributed to the negative exchange coupling between the CoFe and Gd sublattices. This work demonstrates the SOT switching of the nearly compensated ferrimagnet with potential for future magnetic interaction-free and ultrafast ferrimagnetic applications.
Article
Physics, Applied
X. H. Li, M. K. Zhao, R. Zhang, C. H. Wan, Y. Z. Wang, X. M. Luo, S. Q. Liu, J. H. Xia, G. Q. Yu, X. F. Han
Summary: In this work, the authors focus on high-barrier magnetic tunnel junctions (HB-MTJs) based true random number generators (TRNGs). Through experimental and theoretical investigations, they find that HB-MTJs with Y-type spin-orbit torque switching schemes exhibit superior tunability in randomness and enhanced robustness against external disturbances. The random numbers generated by these HB-MTJs have also passed the standardized tests.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Pengwei Dou, Jingyan Zhang, Yaqin Guo, Tao Zhu, Jia Luo, Guoping Zhao, He Huang, Guoqiang Yu, Yunchi Zhao, Jie Qi, Xiao Deng, Yuanbo Wang, Jialiang Li, Jianxin Shen, Xinqi Zheng, Yanfei Wu, Hongxin Yang, Baogen Shen, Shouguo Wang
Summary: This study reports on all electric-controlled magnetization switching in antiferromagnetic Co/Ir/Co trilayers with vertical magnetic imbalance. The switching polarity can be reversed by optimizing the Ir thickness. The polarized neutron reflection measurements reveal a canted noncollinear spin configuration in Co/Ir/Co trilayers, resulting from magnetic inhomogeneity. Micromagnetic simulations demonstrate asymmetric domain walls, caused by introduced imbalance magnetism, leading to deterministic magnetization switching in Co/Ir/Co trilayers.
Article
Chemistry, Multidisciplinary
Bin He, Riccardo Tomasello, Xuming Luo, Ran Zhang, Zhuyang Nie, Mario Carpentieri, Xiufeng Han, Giovanni Finocchio, Guoqiang Yu
Summary: This study demonstrates the realization of a 9-bit skyrmion racetrack memory with all-electrical controllable functionalities in the same device. By generating a tailored nonuniform distribution of magnetic anisotropy through laser irradiation, robust control of skyrmion nucleation and position as well as effective electrical detection of skyrmions are achieved.
Article
Physics, Multidisciplinary
Huimin Sun, Yizhou Liu, Daiqiang Huang, Yu Fu, Yu Huang, Mengyun He, Xuming Luo, Wenjie Song, Yang Liu, Guoqiang Yu, Qing Lin He
Summary: By magnetically doping a single layer TI, the authors observe a zero-field magnetization of the TI that can be switched by dc current. This switching behavior is nonvolatile under zero field but becomes volatile otherwise.
COMMUNICATIONS PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Tianyi Ma, Yu Zhu, Pambiang Abel Dainone, Tongxin Chen, Xavier Devaux, Caihua Wan, Sylvie Migot, Gwladys Lengaigne, Michel Vergnat, Yu Yan, Xiufeng Han, Yuan Lu
Summary: This study demonstrates a large sign reversal of tunneling magnetoresistance (TMR) in a Fe/MgAlOx/Fe4N magnetic tunnel junction (MTJ) controlled by the bias voltage. The sign reversal effect is doubled compared to Fe/MgO/Fe4N MTJs, thanks to the better lattice mismatch and less N diffusion. First-principles calculations reveal that the change of TMR sign originates from different symmetry-dependent tunneling channels between Fe and Fe4N electrodes under opposite bias voltages.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
