1
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Deng Y, Wang M, Xiang Z, Zhu K, Hu T, Lu L, Wang Y, Ma Y, Lei B, Chen X. Room-Temperature Highly Efficient Nonvolatile Magnetization Switching by Current in van der Waals Fe 3GaTe 2 Devices. NANO LETTERS 2024. [PMID: 39017705 DOI: 10.1021/acs.nanolett.4c02227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
The ability to manipulate magnetic states by a low electric current represents a fundamental desire in spintronics. In recent years, two-dimensional van der Waals (vdW) magnetic materials have attracted an extensive amount of attention due to their appreciable spin-orbit torque effect. However, for most known vdW ferromagnets, their relatively low Curie temperatures (TC) limit their applications. Consequently, low-power vdW spintronic devices that can operate at room temperature are in great demand. In this research, we fabricate nanodevices based on a solitary thin flake of vdW ferromagnet Fe3GaTe2, in which we successfully achieve nonvolatile and highly efficient magnetization switching by small currents at room temperature. Notably, the switching current density and the switching power dissipation are as low as 1.7 × 105 A/cm2 and 1.6 × 1013 W/m3, respectively, with an external magnetic field of 80 Oe; both are much reduced compared to those of conventional magnet/heavy metal heterostructure devices and other vdW devices.
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Affiliation(s)
- Yazhou Deng
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Mingjie Wang
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Ziji Xiang
- CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Kejia Zhu
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Tao Hu
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Longyu Lu
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Yu Wang
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Yupeng Ma
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Bin Lei
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Xianhui Chen
- CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei, Anhui 230026, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, China
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2
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Xu X, Zhang D, Liao Z, Yan P, Wang Y, Zhang L, Zhong Z, Bai F, Qu Y, Zhang H, Jin L. Colossal Orbital Current Induced by Gradient Oxidation for High-Efficiency Magnetization Switching. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2403881. [PMID: 39004854 DOI: 10.1002/smll.202403881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 06/19/2024] [Indexed: 07/16/2024]
Abstract
Orbital angular momentum flow can be used to develop a low-dissipation electronic information device by manipulating the orbital current. However, efficiently generating and fully harnessing orbital currents is a formidable challenge. In this study, an approach is presented that induces a colossal orbital current by gradient oxidation in Pt/Ta to enhance spin-orbit torque (SOT) and achieve high-efficiency magnetization switching. The maximum efficiency of the SOT before and after the gradient oxidation of Ta is improved relative to that of Pt by ≈600 and 1200%, respectively. The large SOT originates from the colossal orbital current because of the orbital Rashba-Edelstein effect induced by the gradient oxidation of Ta. In addition, a large spin-to-charge conversion efficiency is observed in yttrium iron garnet/Pt/TaOx because of the inverse orbital Rashba-Edelstein effect. Harnessing the orbital current can help effectively minimize the critical current density of the current-induced magnetization switching to 2.26-1.08 × 106 A cm-2, marking a 12-fold reduction compared to that using Pt. This findings provide a new path for research on low-dissipation spin-orbit devices and improve the tunability of orbital current generation.
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Affiliation(s)
- Xinkai Xu
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Dainan Zhang
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Zhimin Liao
- State key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing, 100871, P. R. China
| | - Peng Yan
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Yixin Wang
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Lei Zhang
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Zhiyong Zhong
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Feiming Bai
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Yuanjing Qu
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Huaiwu Zhang
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
| | - Lichuan Jin
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China
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3
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Liang X, Lv P, Xiong Y, Chen X, Fu D, Feng Y, Wang X, Chen X, Xu G, Kan E, Xu F, Zeng H. Moiré Engineering of Spin-Orbit Torque by Twisted WS 2 Homobilayers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2313059. [PMID: 38871341 DOI: 10.1002/adma.202313059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 05/28/2024] [Indexed: 06/15/2024]
Abstract
Artificial moiré superlattices created by stacking 2D crystals have emerged as a powerful platform with unprecedented material-engineering capabilities. While moiré superlattices are reported to host a number of novel quantum states, their potential for spintronic applications remains largely unexplored. Here, the effective manipulation of spin-orbit torque (SOT) is demonstrated using moiré superlattices in ferromagnetic devices comprised of twisted WS2/WS2 homobilayer (t-WS2) and CoFe/Pt thin films by altering twisting angle (θ) and gate voltage. Notably, a substantial enhancement of up to 44.5% is observed in SOT conductivity at θ ≈ 8.3°. Furthermore, compared to the WS2 monolayer and untwisted WS2/WS2 bilayers, the moiré superlattices in t-WS2 enable a greater gate-voltage tunability of SOT conductivity. These results are related to the generation of the interfacial moiré magnetic field by the real-space Berry phase in moiré superlattices, which modulates the absorption of the spin-Hall current arising from Pt through the magnetic proximity effect. This study highlights the moiré physics as a new building block for designing enhanced spintronic devices.
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Affiliation(s)
- Xiaorong Liang
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Penghao Lv
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Yunhai Xiong
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Xi Chen
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Di Fu
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Yiping Feng
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Xusheng Wang
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Xiang Chen
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Guizhou Xu
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Erjun Kan
- MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing, School of Physics, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Feng Xu
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Haibo Zeng
- MIIT Key Laboratory of Advanced Display Materials and Devices, Institute of Optoelectronics and Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
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4
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Guo Y, Zhang J, Zhu Z, Jiang Y, Jiang L, Wu C, Dong J, Xu X, He W, He B, Huang Z, Du L, Zhang G, Wu K, Han X, Shao D, Yu G, Wu H. Direct and Inverse Spin Splitting Effects in Altermagnetic RuO 2. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2400967. [PMID: 38626379 PMCID: PMC11220717 DOI: 10.1002/advs.202400967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/18/2024] [Indexed: 04/18/2024]
Abstract
Recently, the altermagnetic materials with spin splitting effect (SSE), have drawn significant attention due to their potential to the flexible control of the spin polarization by the Néel vector. Here, the direct and inverse altermagnetic SSE (ASSE) in the (101)-oriented RuO2 film with the tilted Néel vector are reported. First, the spin torque along the x-, y-, and z-axis is detected from the spin torque-induced ferromagnetic resonance (ST-FMR), and the z-spin torque emerges when the electric current is along the [010] direction, showing the anisotropic spin splitting of RuO2. Further, the current-induced modulation of damping is used to quantify the damping-like torque efficiency (ξDL) in RuO2/Py, and an anisotropic ξDL is obtained and maximized for the current along the [010] direction, which increases with the reduction of the temperature, indicating the present of ASSE. Next, by way of spin pumping measurement, the inverse altermagnetic spin splitting effect (IASSE) is studied, which also shows a crystal direction-dependent anisotropic behavior and temperature-dependent behavior. This work gives a comprehensive study of the direct and inverse ASSE effects in the altermagnetic RuO2, inspiring future altermagnetic materials and devices with flexible control of spin polarization.
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Affiliation(s)
- Yaqin Guo
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
| | - Jing Zhang
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
| | - Zengtai Zhu
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
| | - Yuan‐yuan Jiang
- Key Laboratory of Materials PhysicsInstitute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei230031China
- University of Science and Technology of ChinaHefei230026China
| | - Longxing Jiang
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
| | - Chuangwen Wu
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
| | - Jing Dong
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
| | - Xing Xu
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
| | - Wenqing He
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
| | - Bin He
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
| | - Zhiheng Huang
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
| | - Luojun Du
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
| | - Guangyu Zhang
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
| | - Kehui Wu
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
| | - Xiufeng Han
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
| | - Ding‐fu Shao
- Key Laboratory of Materials PhysicsInstitute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei230031China
- University of Science and Technology of ChinaHefei230026China
| | - Guoqiang Yu
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
| | - Hao Wu
- Songshan Lake Materials LaboratoryDongguanGuangdong523808China
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
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5
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Qu Y, Xu X, Zhang L, Wang Y, Zhong Z, Zhang H, Pan L, Lu G, Jin L. Enhanced Spin-Orbit Torque Efficiency in Platinum-Gadolinium Oxide Nanocomposite Films. ACS APPLIED MATERIALS & INTERFACES 2024; 16:31438-31446. [PMID: 38843313 DOI: 10.1021/acsami.4c02911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Spin-orbit torque (SOT) has emerged as an effective means of manipulating magnetization. However, the current energy efficiency of SOT operation is inefficient due to low damping-like SOT efficiency per unit current bias. In this work, we dope conventional rare earth oxides, GdOy, into highly conductive platinum by magnetron sputtering to form a new group of spin Hall materials. A large damping-like spin-orbit torque (DL-SOT) efficiency of about 0.35 ± 0.013 is obtained in Pt0.70(GdOy)0.30 measured by the spin-torque ferromagnetic resonance (ST-FMR) technique, which is about five times that of pure Pt under the same conditions. The substantial enhancement of the spin Hall effect is revealed by theoretical analysis to be attributed to the strong side jump induced by the rare earth oxide GdOy impurities. Moreover, this large DL-SOT efficiency contributes to a low critical switching current density (8.0 × 106 A·cm-2 in the Pt0.70(GdOy)0.30 layer) in current-induced magnetization switching measurements. This systematic study on SOT switching properties suggests that Pt1-x(GdOy)x is an attractive spin current source with large DL-SOT efficiency for future SOT applications and provides another idea to regulate the spin Hall angle.
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Affiliation(s)
- Yuanjing Qu
- Hubei Engineering Research Center of Weak Magnetic-field Detection, College of Science, China Three Gorges University, Yichang 443002, China
| | - Xinkai Xu
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Lei Zhang
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Yixin Wang
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Zhiyong Zhong
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Huaiwu Zhang
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Liqing Pan
- Hubei Engineering Research Center of Weak Magnetic-field Detection, College of Science, China Three Gorges University, Yichang 443002, China
| | - Guangduo Lu
- Hubei Engineering Research Center of Weak Magnetic-field Detection, College of Science, China Three Gorges University, Yichang 443002, China
| | - Lichuan Jin
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
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6
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Wang F, Shi G, Kim KW, Park HJ, Jang JG, Tan HR, Lin M, Liu Y, Kim T, Yang D, Zhao S, Lee K, Yang S, Soumyanarayanan A, Lee KJ, Yang H. Field-free switching of perpendicular magnetization by two-dimensional PtTe 2/WTe 2 van der Waals heterostructures with high spin Hall conductivity. NATURE MATERIALS 2024; 23:768-774. [PMID: 38243113 DOI: 10.1038/s41563-023-01774-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 11/28/2023] [Indexed: 01/21/2024]
Abstract
The key challenge of spin-orbit torque applications lies in exploring an excellent spin source capable of generating out-of-plane spins while exhibiting high spin Hall conductivity. Here we combine PtTe2 for high spin conductivity and WTe2 for low crystal symmetry to satisfy the above requirements. The PtTe2/WTe2 bilayers exhibit a high in-plane spin Hall conductivity σs,y ≈ 2.32 × 105 × ħ/2e Ω-1 m-1 and out-of-plane spin Hall conductivity σs,z ≈ 0.25 × 105 × ħ/2e Ω-1 m-1, where ħ is the reduced Planck's constant and e is the value of the elementary charge. The out-of-plane spins in PtTe2/WTe2 bilayers enable the deterministic switching of perpendicular magnetization at room temperature without magnetic fields, and the power consumption is 67 times smaller than that of the Pt control case. The high out-of-plane spin Hall conductivity is attributed to the conversion from in-plane spin to out-of-plane spin, induced by the crystal asymmetry of WTe2. Our work establishes a low-power perpendicular magnetization manipulation based on wafer-scale two-dimensional van der Waals heterostructures.
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Affiliation(s)
- Fei Wang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Guoyi Shi
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
- Integrative Sciences and Engineering Programme, NUS Graduate School, National University of Singapore, Singapore, Singapore
| | - Kyoung-Whan Kim
- Center of Spintronics, Korea Institute of Science and Technology, Seoul, Korea
| | - Hyeon-Jong Park
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Korea
| | - Jae Gwang Jang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Hui Ru Tan
- Institute of Materials Research & Engineering, Agency for Science Technology & Research (A*STAR), Singapore, Singapore
| | - Ming Lin
- Institute of Materials Research & Engineering, Agency for Science Technology & Research (A*STAR), Singapore, Singapore
| | - Yakun Liu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Taeheon Kim
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Dongsheng Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Shishun Zhao
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Kyusup Lee
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Shuhan Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Anjan Soumyanarayanan
- Institute of Materials Research & Engineering, Agency for Science Technology & Research (A*STAR), Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Kyung-Jin Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
- Integrative Sciences and Engineering Programme, NUS Graduate School, National University of Singapore, Singapore, Singapore.
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7
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Choi GS, Park S, An ES, Bae J, Shin I, Kang BT, Won CJ, Cheong SW, Lee HW, Lee GH, Cho WJ, Kim JS. Highly Efficient Room-Temperature Spin-Orbit-Torque Switching in a Van der Waals Heterostructure of Topological Insulator and Ferromagnet. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2400893. [PMID: 38520060 DOI: 10.1002/advs.202400893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Indexed: 03/25/2024]
Abstract
All-Van der Waals (vdW)-material-based heterostructures with atomically sharp interfaces offer a versatile platform for high-performing spintronic functionalities at room temperature. One of the key components is vdW topological insulators (TIs), which can produce a strong spin-orbit-torque (SOT) through the spin-momentum locking of their topological surface state (TSS). However, the relatively low conductance of the TSS introduces a current leakage problem through the bulk states of the TI or the adjacent ferromagnetic metal layers, reducing the interfacial charge-to-spin conversion efficiency (qICS). Here, a vdW heterostructure is used consisting of atomically-thin layers of a bulk-insulating TI Sn-doped Bi1.1Sb0.9Te2S1 and a room-temperature ferromagnet Fe3GaTe2, to enhance the relative current ratio on the TSS up to ≈20%. The resulting qICS reaches ≈1.65 nm-1 and the critical current density Jc ≈0.9 × 106 Acm-2 at 300 K, surpassing the performance of TI-based and heavy-metal-based SOT devices. These findings demonstrate that an all-vdW heterostructure with thickness optimization offers a promising platform for efficient current-controlled magnetization switching at room temperature.
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Affiliation(s)
- Gyu Seung Choi
- 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
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, 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
| | - Juhong Bae
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Inseob Shin
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Beom Tak Kang
- 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
| | - Choong Jae Won
- Center for Complex Phase of Materials, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Republic of Korea
- Laboratory for Pohang Emergent Materials, Department of Physics, POSTECH, Pohang, 37673, Republic of Korea
| | - Sang-Wook Cheong
- Center for Complex Phase of Materials, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Republic of Korea
- Laboratory for Pohang Emergent Materials, Department of Physics, POSTECH, Pohang, 37673, Republic of Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Hyun-Woo Lee
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Gil-Ho Lee
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Won Joon Cho
- Device 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
| | - 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
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8
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Yan S, Tian S, Fu Y, Meng F, Li Z, Lei H, Wang S, Zhang X. Highly Efficient Room-Temperature Nonvolatile Magnetic Switching by Current in Fe 3GaTe 2 Thin Flakes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2311430. [PMID: 38444270 DOI: 10.1002/smll.202311430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 12/13/2023] [Indexed: 03/07/2024]
Abstract
Effectively tuning magnetic state by using current is essential for novel spintronic devices. Magnetic van der Waals (vdW) materials have shown superior properties for the applications of magnetic information storage based on the efficient spin torque effect. However, for most of known vdW ferromagnets, the ferromagnetic transition temperatures lower than room temperature strongly impede their applications and the room-temperature vdW spintronic device with low energy consumption is still a long-sought goal. Here, the highly efficient room-temperature nonvolatile magnetic switching is realized by current in a single-material device based on vdW ferromagnet Fe3GaTe2. Moreover, the switching current density and power dissipation are about 300 and 60000 times smaller than conventional spin-orbit-torque devices of magnet/heavy-metal heterostructures. These findings make an important progress on the applications of magnetic vdW materials in the fields of spintronics and magnetic information storage.
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Affiliation(s)
- Shaohua Yan
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Shangjie Tian
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Yang Fu
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Fanyu Meng
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Zhiteng Li
- State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications, Beijing, 100876, China
| | - Hechang Lei
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & MicroNano Devices, Renmin University of China, Beijing, 100872, China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China
| | - Shouguo Wang
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Xiao Zhang
- State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications, Beijing, 100876, China
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9
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Farokhnezhad M, Cullen JH, Culcer D. Spin-orbit torques due to topological insulator surface states: an in-plane magnetization as a probe of extrinsic spin-orbit scattering. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:315004. [PMID: 38663418 DOI: 10.1088/1361-648x/ad43a6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 04/25/2024] [Indexed: 05/09/2024]
Abstract
Topological insulator (TI) surface states exert strong spin-orbit torques. When the magnetization is in the plane its interaction with the TI conduction electrons is non-trivial, and is influenced by extrinsic spin-orbit scattering. This is expected to be strong in TIs but is difficult to calculate and to measure unambiguously. Here we show that extrinsic spin-orbit scattering sizably renormalizes the surface state spin-orbit torque resulting in a strong density dependence. The magnitude of the renormalization of the spin torque and the effect of spin-orbit scattering on the relative sizes of the in-plane and out-of-plane field-like torques have strong implications for experiment: We propose two separate experimental signatures for the measurement of its presence.
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Affiliation(s)
- Mohsen Farokhnezhad
- Department of Physics, School of Science, Shiraz University, Shiraz 71946-84795, Iran
- School of Nanoscience, Institute for Research in Fundamental Sciences, IPM, Tehran 19395-5531, Iran
- School of Physics, Institute for Research in Fundamental Sciences, IPM, Tehran 19395-5531, Iran
| | - James H Cullen
- School of Physics, University of New South Wales, Kensington, NSW 2052, Australia
| | - Dimitrie Culcer
- School of Physics, University of New South Wales, Kensington, NSW 2052, Australia
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10
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Yadav P, Xinhou C, Bhatt S, Das S, Yang H, Mishra R. Highly Efficient Spintronic Terahertz Emitter Utilizing a Large Spin Hall Conductivity of Type-II Dirac Semimetal PtTe 2. NANO LETTERS 2024; 24:2376-2383. [PMID: 38329912 DOI: 10.1021/acs.nanolett.3c04986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
The remarkable spin-charge interconversion ability of transition metal dichalcogenides (TMDs) makes them promising candidates for spintronic applications. Nevertheless, their potential as spintronic terahertz (THz) emitters (STEs) remains constrained mainly due to their sizable resistivity and low spin Hall conductivity (SHC), which consequently result in modest THz emission. In this work, the TMD PtTe2, a type-II Dirac semimetal is effectively utilized to develop efficient STEs. This high efficiency primarily results from the large SHC of PtTe2, stemming from its low resistivity and significant spin-to-charge conversion efficiency, attributed to surface states and the local Rashba effect in addition to the inverse spin Hall effect. Remarkably, the peak THz emission from PtTe2/Co-STE exceeds that of Pt/Co-STE by ∼15% and is nearly double that of a similarly thick Pt/Co-STE. The efficient THz emission in the PtTe2/Co heterostructure opens new possibilities for utilizing the semimetal TMDs for developing THz emitters.
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Affiliation(s)
- Pinki Yadav
- Center for Applied Research in Electronics, Indian Institute of Technology Delhi, Delhi 110016, India
| | - Chen Xinhou
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576
| | - Shubham Bhatt
- Center for Applied Research in Electronics, Indian Institute of Technology Delhi, Delhi 110016, India
| | - Samaresh Das
- Center for Applied Research in Electronics, Indian Institute of Technology Delhi, Delhi 110016, India
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576
| | - Rahul Mishra
- Center for Applied Research in Electronics, Indian Institute of Technology Delhi, Delhi 110016, India
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11
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Guillet T, Galceran R, Sierra JF, Belarre FJ, Ballesteros B, Costache MV, Dosenovic D, Okuno H, Marty A, Jamet M, Bonell F, Valenzuela SO. Spin-Orbit Torques and Magnetization Switching in (Bi,Sb) 2Te 3/Fe 3GeTe 2 Heterostructures Grown by Molecular Beam Epitaxy. NANO LETTERS 2024; 24:822-828. [PMID: 38263950 DOI: 10.1021/acs.nanolett.3c03291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Topological insulators (TIs) hold promise for manipulating the magnetization of a ferromagnet (FM) through the spin-orbit torque (SOT) mechanism. However, integrating TIs with conventional FMs often leads to significant device-to-device variations and a broad distribution of SOT magnitudes. In this work, we present a scalable approach to grow a full van der Waals FM/TI heterostructure by molecular beam epitaxy, combining the charge-compensated TI (Bi,Sb)2Te3 with 2D FM Fe3GeTe2 (FGT). Harmonic magnetotransport measurements reveal that the SOT efficiency exhibits a non-monotonic temperature dependence and experiences a substantial enhancement with a reduction of the FGT thickness to 2 monolayers. Our study further demonstrates that the magnetization of ultrathin FGT films can be switched with a current density of Jc ∼ 1010 A/m2, with minimal device-to-device variations compared to previous investigations involving traditional FMs.
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Affiliation(s)
- Thomas Guillet
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Regina Galceran
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Juan F Sierra
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Francisco J Belarre
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Belén Ballesteros
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Marius V Costache
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | | | - Hanako Okuno
- Univ. Grenoble Alpes, CEA, IRIG-MEM, 38000 Grenoble, France
| | - Alain Marty
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000 Grenoble, France
| | - Matthieu Jamet
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000 Grenoble, France
| | - Frédéric Bonell
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000 Grenoble, France
| | - Sergio O Valenzuela
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08070 Barcelona, Spain
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12
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Mudgal R, Jakhar A, Gupta P, Yadav RS, Biswal B, Sahu P, Bangar H, Kumar A, Chowdhury N, Satpati B, Kumar Nanda BR, Satpathy S, Das S, Muduli PK. Magnetic-Proximity-Induced Efficient Charge-to-Spin Conversion in Large-Area PtSe 2/Ni 80Fe 20 Heterostructures. NANO LETTERS 2023; 23:11925-11931. [PMID: 38088819 DOI: 10.1021/acs.nanolett.3c04060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
As a topological Dirac semimetal with controllable spin-orbit coupling and conductivity, PtSe2, a transition-metal dichalcogenide, is a promising material for several applications, from optoelectrics to sensors. However, its potential for spintronics applications has yet to be explored. In this work, we demonstrate that the PtSe2/Ni80Fe20 heterostructure can generate large damping-like current-induced spin-orbit torques (SOT), despite the absence of spin-splitting in bulk PtSe2. The efficiency of charge-to-spin conversion is found to be -0.1 ± 0.02 nm-1 in PtSe2/Ni80Fe20, which is 3 times that of the control sample, Ni80Fe20/Pt. Our band structure calculations show that the SOT due to PtSe2 arises from an unexpectedly large spin splitting in the interfacial region of PtSe2 introduced by the proximity magnetic field of the Ni80Fe20 layer. Our results open up the possibilities of using large-area PtSe2 for energy-efficient nanoscale devices by utilizing proximity-induced SOT.
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Affiliation(s)
- Richa Mudgal
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Alka Jakhar
- Center for Applied Research in Electronics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Pankhuri Gupta
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Ram Singh Yadav
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Bubunu Biswal
- Condensed Matter Theory and Computational Lab, Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
- Center for Atomistic Modelling and Materials Design, Indian Institute of Technology Madras, Chennai 600036, India
| | - Pratik Sahu
- Condensed Matter Theory and Computational Lab, Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
- Department of Physics & Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Himanshu Bangar
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Akash Kumar
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
- Department of Physics, University of Gothenburg, Gothenburg 412 96, Sweden
| | - Niru Chowdhury
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Biswarup Satpati
- Surface Physics & Material Science Division, Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute, 1/AF Bidhannagar, Kolkata 700064, India
| | - Birabar Ranjit Kumar Nanda
- Condensed Matter Theory and Computational Lab, Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
- Center for Atomistic Modelling and Materials Design, Indian Institute of Technology Madras, Chennai 600036, India
| | - Sashi Satpathy
- Condensed Matter Theory and Computational Lab, Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
- Center for Atomistic Modelling and Materials Design, Indian Institute of Technology Madras, Chennai 600036, India
- Department of Physics & Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Samaresh Das
- Center for Applied Research in Electronics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Pranaba Kishor Muduli
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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13
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Jain R, Stanley M, Bose A, Richardella AR, Zhang XS, Pillsbury T, Muller DA, Samarth N, Ralph DC. Thermally generated spin current in the topological insulator Bi 2Se 3. SCIENCE ADVANCES 2023; 9:eadi4540. [PMID: 38091392 PMCID: PMC10848729 DOI: 10.1126/sciadv.adi4540] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 11/14/2023] [Indexed: 02/12/2024]
Abstract
We present measurements of thermally generated transverse spin currents in the topological insulator Bi2Se3, thereby completing measurements of interconversions among the full triad of thermal gradients, charge currents, and spin currents. We accomplish this by comparing the spin Nernst magneto-thermopower to the spin Hall magnetoresistance for bilayers of Bi2Se3/CoFeB. We find that Bi2Se3 does generate substantial thermally driven spin currents. A lower bound for the ratio of spin current density to thermal gradient is [Formula: see text] = (4.9 ± 0.9) × 106 [Formula: see text], and a lower bound for the magnitude of the spin Nernst ratio is -0.61 ± 0.11. The spin Nernst ratio for Bi2Se3 is the largest among all materials measured to date, two to three times larger compared to previous measurements for the heavy metals Pt and W. Strong thermally generated spin currents in Bi2Se3 can be understood via Mott relations to be due to an overall large spin Hall conductivity and its dependence on electron energy.
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Affiliation(s)
- Rakshit Jain
- Department of Physics, Cornell University, Ithaca, NY 14853, USA
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
| | - Max Stanley
- Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA
| | - Arnab Bose
- Department of Physics, Cornell University, Ithaca, NY 14853, USA
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
| | - Anthony R. Richardella
- Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA
| | - Xiyue S. Zhang
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
| | - Timothy Pillsbury
- Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA
| | - David A. Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, USA
| | - Nitin Samarth
- Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802, USA
| | - Daniel C. Ralph
- Department of Physics, Cornell University, Ithaca, NY 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, USA
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14
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Binda F, Fedel S, Alvarado SF, Noël P, Gambardella P. Spin-Orbit Torques and Spin Hall Magnetoresistance Generated by Twin-Free and Amorphous Bi 0.9 Sb 0.1 Topological Insulator Films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2304905. [PMID: 37568279 DOI: 10.1002/adma.202304905] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/28/2023] [Indexed: 08/13/2023]
Abstract
Topological insulators have attracted great interest as generators of spin-orbit torques (SOTs) in spintronic devices. Bi1-x Sbx is a prominent topological insulator that has a high charge-to-spin conversion efficiency. However, the origin and magnitude of the SOTs induced by current-injection in Bi1-x Sbx remain controversial. Here, the investigation of the SOTs and spin Hall magnetoresistance resulting from charge-to-spin conversion in twin-free epitaxial layers of Bi0.9 Sb0.1 (0001) coupled to FeCo are investigated, and compared with those of amorphous Bi0.9 Sb0.1 . A large charge-to-spin conversion efficiency of 1 in the first case and less than 0.1 in the second is found, confirming crystalline Bi0.9 Sb0.1 as a strong spin-injector material. The SOTs and spin Hall magnetoresistance are independent of the direction of the electric current, indicating that charge-to-spin conversion in single-crystal Bi0.9 Sb0.1 (0001) is isotropic despite the strong anisotropy of the topological surface states. Further, it is found that the damping-like SOT has a non-monotonic temperature dependence with a minimum at 20 K. By correlating the SOT with resistivity and weak antilocalization measurements, charge-spin conversion is concluded to occur via thermally excited holes from the bulk states above 20 K, and conduction through the isotropic surface states with increasing spin polarization due to decreasing electron-electron scattering below 20 K.
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Affiliation(s)
- Federico Binda
- Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Stefano Fedel
- Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
| | | | - Paul Noël
- Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
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15
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Kim S, Lee H, Choi G. Giant Spin-Orbit Torque in Sputter-Deposited Bi Films. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2303831. [PMID: 37679062 PMCID: PMC10625106 DOI: 10.1002/advs.202303831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Indexed: 09/09/2023]
Abstract
Bismuth (Bi) has the strongest spin-orbit coupling among non-radioactive elements and is thus a promising material for efficient charge-to-spin conversion. However, previous electrical detections have reported controversial results for the conversion efficiency. In this study, an optical detection of a spin-orbit torque is reported in a Bi/CoFeB bilayer with a polycrystalline texture of (012) and (003). Taking advantage of the optical detection, spin-orbit torque is accurately separated from the Oersted field and achieves a giant damping-like torque efficiency of +0.5, verifying efficient charge-to-spin conversion. This study also demonstrates a field-like torque efficiency of -0.1. For the mechanism of the charge-to-spin conversion, the bulk spin Hall effect and the interface Rashba-Edelstein effect are considered.
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Affiliation(s)
- Sumin Kim
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419South Korea
| | - Hyun‐Woo Lee
- Department of PhysicsPohang University of Science and TechnologyPohang37673South Korea
- Asia Pacific Center for Theoretical Physics77 Cheongam‐roPohang37673South Korea
| | - Gyung‐Min Choi
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419South Korea
- Center for Integrated Nanostructure PhysicsInstitute for Basic ScienceSungkyunkwan UniversitySuwon16419South Korea
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16
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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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17
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Zhang J, Zhao Y, Dou P, Peng W, Huang H, Deng X, Wang Y, Liu J, Xu J, Zhu T, Qi J, Zheng X, Wu Y, Shen B, Wang S. Controllable Spin-Orbit Torque Induced by Interfacial Ion Absorption in Ta/CoFeB/MgO Multilayers with Canted Magnetizations. ACS APPLIED MATERIALS & INTERFACES 2023; 15:49902-49910. [PMID: 37815887 DOI: 10.1021/acsami.3c12551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
Electrically generated spin-orbit torque (SOT) has emerged as a powerful pathway to control magnetization for spintronic applications including memory, logic, and neurocomputing. However, the requirement of external magnetic fields, together with the ultrahigh current density, is the main obstacle for practical SOT devices. In this paper, we report that the field-free SOT-driven magnetization switching can be successfully realized by interfacial ion absorption in perpendicular Ta/CoFeB/MgO multilayers. Besides, the tunable SOT efficiency exhibits a strong dependence on interfacial Ti insertion thicknesses. Polarized neutron reflection measurements demonstrate the existence of canted magnetization with Ti inserted, which leads to deterministic magnetization switching. In addition, interfacial characterization and first-principles calculations reveal that B absorption by the Ti layer is the main cause behind the enhanced interfacial transparency, which determines the tunable SOT efficiency. Our findings highlight an attractive scheme to a purely electric control spin configuration, enabling innovative designs for SOT-based spintronics via interfacial engineering.
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Affiliation(s)
- Jingyan Zhang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yunchi Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Pengwei Dou
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Wenlin Peng
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - He Huang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xiao Deng
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yuanbo Wang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jialong Liu
- Department of Physics and Electronics, School of Mathematics and Physics, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jiawang Xu
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei 230601, China
| | - Tao Zhu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jie Qi
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xinqi Zheng
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yanfei Wu
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shouguo Wang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei 230601, China
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18
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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: 14] [Impact Index Per Article: 14.0] [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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19
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Sahu P, Yang Y, Fan Y, Jaffrès H, Chen JY, Devaux X, Fagot-Revurat Y, Migot S, Rongione E, Chen T, Abel Dainone P, George JM, Dhillon S, Micica M, Lu Y, Wang JP. Room Temperature Spin-to-Charge Conversion in Amorphous Topological Insulating Gd-Alloyed Bi xSe 1-x/CoFeB Bilayers. ACS APPLIED MATERIALS & INTERFACES 2023; 15:38592-38602. [PMID: 37550946 DOI: 10.1021/acsami.3c07695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
Disordered topological insulator (TI) films have gained intense interest by benefiting from both the TI's exotic transport properties and the advantage of mass production by sputtering. Here, we report on the clear evidence of spin-charge conversion (SCC) in amorphous Gd-alloyed BixSe1-x (BSG)/CoFeB bilayers fabricated by sputtering, which could be related to the amorphous TI surface states. Two methods have been employed to study SCC in BSG (tBSG = 6-16 nm)/CoFeB(5 nm) bilayers with different BSG thicknesses. First, spin pumping is used to generate a spin current in CoFeB and detect SCC by the inverse Edelstein effect (IEE). The maximum SCC efficiency (SCE) is measured to be as large as 0.035 nm (IEE length λIEE) in a 6 nm thick BSG sample, which shows a strong decay when tBSG increases due to the increase of BSG surface roughness. The second method is THz time-domain spectroscopy, which reveals a small tBSG dependence of SCE, validating the occurrence of a pure interface state-related SCC. Furthermore, our angle-resolved photoemission spectroscopy data show dispersive two-dimensional surface states that cross the bulk gap until the Fermi level, strengthening the possibility of SCC due to the amorphous TI states. Our studies provide a new experimental direction toward the search for topological systems in amorphous solids.
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Affiliation(s)
- Protyush Sahu
- School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, Minnesota 55455, United States
| | - Yifei Yang
- Department of Electrical and Computer Engineering, University of Minnesota, 200 Union Street SE, Minneapolis, Minnesota 55455, United States
| | - Yihong Fan
- Department of Electrical and Computer Engineering, University of Minnesota, 200 Union Street SE, Minneapolis, Minnesota 55455, United States
| | - Henri Jaffrès
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Jun-Yang Chen
- Department of Electrical and Computer Engineering, University of Minnesota, 200 Union Street SE, Minneapolis, Minnesota 55455, United States
| | - Xavier Devaux
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Yannick Fagot-Revurat
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Sylvie Migot
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Enzo Rongione
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005 Paris, France
| | - Tongxin Chen
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Pambiang Abel Dainone
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Jean-Marie George
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Sukhdeep Dhillon
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005 Paris, France
| | - Martin Micica
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005 Paris, France
| | - Yuan Lu
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Jian-Ping Wang
- School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, Minnesota 55455, United States
- Department of Electrical and Computer Engineering, University of Minnesota, 200 Union Street SE, Minneapolis, Minnesota 55455, United States
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20
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Krishnia S, Sassi Y, Ajejas F, Sebe N, Reyren N, Collin S, Denneulin T, Kovács A, Dunin-Borkowski RE, Fert A, George JM, Cros V, Jaffrès H. Large Interfacial Rashba Interaction Generating Strong Spin-Orbit Torques in Atomically Thin Metallic Heterostructures. NANO LETTERS 2023; 23:6785-6791. [PMID: 37524333 PMCID: PMC10416352 DOI: 10.1021/acs.nanolett.2c05091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 06/22/2023] [Indexed: 08/02/2023]
Abstract
The hallmark of spintronics has been the ability of spin-orbit interactions to convert a charge current into a spin current and vice versa, mainly in the bulk of heavy metal thin films. Here, we demonstrate how a light metal interface profoundly affects both the nature of spin-orbit torques and its efficiency in terms of damping-like (HDL) and field-like (HFL) effective fields in ultrathin Co films. We measure unexpectedly HFL/HDL ratios much larger than 1 by inserting a nanometer-thin Al metallic layer in Pt|Co|Al|Pt as compared to a similar stacking, including Cu as a reference. From our modeling, these results evidence the existence of large Rashba interaction at the Co|Al interface generating a giant HFL, which is not expected from a metallic interface. The occurrence of such enhanced torques from an interfacial origin is further validated by demonstrating current-induced magnetization reversal showing a significant decrease of the critical current for switching.
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Affiliation(s)
- Sachin Krishnia
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Yanis Sassi
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Fernando Ajejas
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Nicolas Sebe
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Nicolas Reyren
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Sophie Collin
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Thibaud Denneulin
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C
1) and Peter Grünberg Institut (PGI-5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - András Kovács
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C
1) and Peter Grünberg Institut (PGI-5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Rafal E. Dunin-Borkowski
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C
1) and Peter Grünberg Institut (PGI-5), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Albert Fert
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Jean-Marie George
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Vincent Cros
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Henri Jaffrès
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
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21
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Jiang M, Asahara H, Ohya S, Tanaka M. Electric Field Control of Spin-Orbit Torque Magnetization Switching in a Spin-Orbit Ferromagnet Single Layer. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2301540. [PMID: 37329321 PMCID: PMC10460875 DOI: 10.1002/advs.202301540] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/29/2023] [Indexed: 06/19/2023]
Abstract
To achieve a desirable magnitude of spin-orbit torque (SOT) for magnetization switching and realize multifunctional spin logic and memory devices utilizing SOT, controlling the SOT manipulation is vitally important. In conventional SOT bilayer systems, researchers have tried to control the magnetization switching behavior via interfacial oxidization, modulation of spin-orbit effective field, and effective spin Hall angle; however, the switching efficiency is limited by the interface quality. A current-induced effective magnetic field in a single layer of a ferromagnet with strong spin-orbit interactions, the so-called spin-orbit ferromagnet, can be utilized to induce SOT. In spin-orbit ferromagnet systems, electric field application has the potential for manipulating the spin-orbit interactions via carrier concentration modulation. In this work, it is demonstrated that SOT magnetization switching can be successfully controlled via an external electric field using a (Ga, Mn)As single layer. By applying a gate voltage, the switching current density can be solidly and reversibly manipulated with a large ratio of 14.5%, which is ascribed to the successful modulation of the interfacial electric field. The findings of this work help further the understanding of the magnetization switching mechanism and advance the development of gate-controlled SOT devices.
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Affiliation(s)
- Miao Jiang
- School of Materials Science and EngineeringBeijing Institute of TechnologyZhongguancun South Street No.5, HaidianBeijing100081China
- Department of Electrical Engineering and Information SystemsThe University of Tokyo7‐3‐1 Hongo, Bunkyo‐kuTokyo113‐8656Japan
| | - Hirokatsu Asahara
- Department of Electrical Engineering and Information SystemsThe University of Tokyo7‐3‐1 Hongo, Bunkyo‐kuTokyo113‐8656Japan
| | - Shinobu Ohya
- Department of Electrical Engineering and Information SystemsThe University of Tokyo7‐3‐1 Hongo, Bunkyo‐kuTokyo113‐8656Japan
- Center for Spintronics Research Network (CSRN)Graduate School of EngineeringThe University of Tokyo7‐3‐1 Hongo, Bunkyo‐kuTokyo113‐8656Japan
| | - Masaaki Tanaka
- Department of Electrical Engineering and Information SystemsThe University of Tokyo7‐3‐1 Hongo, Bunkyo‐kuTokyo113‐8656Japan
- Center for Spintronics Research Network (CSRN)Graduate School of EngineeringThe University of Tokyo7‐3‐1 Hongo, Bunkyo‐kuTokyo113‐8656Japan
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22
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Zhang D, Jiang W, Yun H, Benally OJ, Peterson T, Cresswell Z, Fan Y, Lv Y, Yu G, Barriocanal JG, Swatek PW, Mkhoyan KA, Low T, Wang JP. Robust negative longitudinal magnetoresistance and spin-orbit torque in sputtered Pt 3Sn and Pt 3Sn xFe 1-x topological semimetal. Nat Commun 2023; 14:4151. [PMID: 37438330 DOI: 10.1038/s41467-023-39408-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 06/13/2023] [Indexed: 07/14/2023] Open
Abstract
Contrary to topological insulators, topological semimetals possess a nontrivial chiral anomaly that leads to negative magnetoresistance and are hosts to both conductive bulk states and topological surface states with intriguing transport properties for spintronics. Here, we fabricate highly-ordered metallic Pt3Sn and Pt3SnxFe1-x thin films via sputtering technology. Systematic angular dependence (both in-plane and out-of-plane) study of magnetoresistance presents surprisingly robust quadratic and linear negative longitudinal magnetoresistance features for Pt3Sn and Pt3SnxFe1-x, respectively. We attribute the anomalous negative longitudinal magnetoresistance to the type-II Dirac semimetal phase (pristine Pt3Sn) and/or the formation of tunable Weyl semimetal phases through symmetry breaking processes, such as magnetic-atom doping, as confirmed by first-principles calculations. Furthermore, Pt3Sn and Pt3SnxFe1-x show the promising performance for facilitating the development of advanced spin-orbit torque devices. These results extend our understanding of chiral anomaly of topological semimetals and can pave the way for exploring novel topological materials for spintronic devices.
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Affiliation(s)
- Delin Zhang
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA.
| | - Wei Jiang
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Hwanhui Yun
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Onri Jay Benally
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Thomas Peterson
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Zach Cresswell
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Yihong Fan
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Yang Lv
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Guichuan Yu
- Characterization Facility, University of Minnesota, Minneapolis, MN, 55455, USA
| | | | | | - K Andre Mkhoyan
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Tony Low
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA.
| | - Jian-Ping Wang
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, 55455, USA.
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, 55455, USA.
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23
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Dc M, Shao DF, Hou VDH, Vailionis A, Quarterman P, Habiboglu A, Venuti MB, Xue F, Huang YL, Lee CM, Miura M, Kirby B, Bi C, Li X, Deng Y, Lin SJ, Tsai W, Eley S, Wang WG, Borchers JA, Tsymbal EY, Wang SX. Observation of anti-damping spin-orbit torques generated by in-plane and out-of-plane spin polarizations in MnPd 3. NATURE MATERIALS 2023; 22:591-598. [PMID: 37012436 DOI: 10.1038/s41563-023-01522-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 03/02/2023] [Indexed: 05/05/2023]
Abstract
Large spin-orbit torques (SOTs) generated by topological materials and heavy metals interfaced with ferromagnets are promising for next-generation magnetic memory and logic devices. SOTs generated from y spin originating from spin Hall and Edelstein effects can realize field-free magnetization switching only when the magnetization and spin are collinear. Here we circumvent the above limitation by utilizing unconventional spins generated in a MnPd3 thin film grown on an oxidized silicon substrate. We observe conventional SOT due to y spin, and out-of-plane and in-plane anti-damping-like torques originated from z spin and x spin, respectively, in MnPd3/CoFeB heterostructures. Notably, we have demonstrated complete field-free switching of perpendicular cobalt via out-of-plane anti-damping-like SOT. Density functional theory calculations show that the observed unconventional torques are due to the low symmetry of the (114)-oriented MnPd3 films. Altogether our results provide a path toward realization of a practical spin channel in ultrafast magnetic memory and logic devices.
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Affiliation(s)
- Mahendra Dc
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
| | - Ding-Fu Shao
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, USA
| | | | - Arturas Vailionis
- Stanford Nano Shared Facilities, Stanford University, Stanford, CA, USA
- Department of Physics, Kaunas University of Technology, Kaunas, Lithuania
| | - P Quarterman
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - Ali Habiboglu
- Department of Physics, University of Arizona, Tucson, AZ, USA
| | - M B Venuti
- Department of Physics, Colorado School of Mines, Golden, CO, USA
| | - Fen Xue
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Yen-Lin Huang
- Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| | - Chien-Min Lee
- Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan
| | - Masashi Miura
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
- Graduate School of Science and Technology, Seikei University, Tokyo, Japan
| | - Brian Kirby
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - Chong Bi
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Xiang Li
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Yong Deng
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Shy-Jay Lin
- Taiwan Semiconductor Manufacturing Company, Hsinchu, Taiwan
| | - Wilman Tsai
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Serena Eley
- Department of Physics, Colorado School of Mines, Golden, CO, USA
| | - Wei-Gang Wang
- Department of Physics, University of Arizona, Tucson, AZ, USA
| | - Julie A Borchers
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, USA
| | - Shan X Wang
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA.
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24
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Cullen JH, Atencia RB, Culcer D. Spin transfer torques due to the bulk states of topological insulators. NANOSCALE 2023; 15:8437-8446. [PMID: 37096561 DOI: 10.1039/d2nr05176a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Spin torques at topological insulator (TI)/ferromagnet interfaces have received considerable attention in recent years with a view towards achieving full electrical manipulation of magnetic degrees of freedom. The most important question in this field concerns the relative contributions of bulk and surface states to the spin torque, a matter that remains incompletely understood. Whereas the surface state contribution has been extensively studied, the contribution due to the bulk states has received comparatively little attention. Here we study spin torques due to TI bulk states and show that: (i) there is no spin-orbit torque due to the bulk states on a homogeneous magnetisation, in contrast to the surface states, which give rise to a spin-orbit torque via the well-known Edelstein effect. (ii) The bulk states give rise to a spin transfer torque (STT) due to the inhomogeneity of the magnetisation in the vicinity of the interface. This spin transfer torque, which has not been considered in TIs in the past, is somewhat unconventional since it arises from the interplay of the bulk TI spin-orbit coupling and the gradient of the monotonically decaying magnetisation inside the TI. Whereas we consider an idealised model in which the magnetisation gradient is small and the spin transfer torque is correspondingly small, we argue that in real samples the spin transfer torque should be sizable and may provide the dominant contribution due to the bulk states. We show that an experimental smoking gun for identifying the bulk states is the fact that the field-like component of the spin transfer torque generates a spin density with the same size but opposite sign for in-plane and out-of-plane magnetisations. This distinguishes them from the surface states, which are expected to give a spin density of a similar size and the same sign for both an in-plane and out-of-plane magnetisations.
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Affiliation(s)
- James H Cullen
- School of Physics, The University of New South Wales, Sydney 2052, Australia.
| | - Rhonald Burgos Atencia
- School of Physics, The University of New South Wales, Sydney 2052, Australia.
- Facultad de Ingenierías, Departamento de Ciencias Básicas, Universidad del Sinú, Cra.1w No. 38-153, 4536534, Montería, Córdoba 230002, Colombia
| | - Dimitrie Culcer
- School of Physics, The University of New South Wales, Sydney 2052, Australia.
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25
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Burn DM, Lin JC, Fujita R, Achinuq B, Bibby J, Singh A, Frisk A, van der Laan G, Hesjedal T. Spin pumping through nanocrystalline topological insulators. NANOTECHNOLOGY 2023; 34:275001. [PMID: 36947871 DOI: 10.1088/1361-6528/acc663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/21/2023] [Indexed: 06/18/2023]
Abstract
The topological surface states (TSSs) in topological insulators (TIs) offer exciting prospects for dissipationless spin transport. Common spin-based devices, such as spin valves, rely on trilayer structures in which a non-magnetic layer is sandwiched between two ferromagnetic (FM) layers. The major disadvantage of using high-quality single-crystalline TI films in this context is that a single pair of spin-momentum locked channels spans across the entire film, meaning that only a very small spin current can be pumped from one FM to the other, along the side walls of the film. On the other hand, using nanocrystalline TI films, in which the grains are large enough to avoid hybridization of the TSSs, will effectively increase the number of spin channels available for spin pumping. Here, we used an element-selective, x-ray based ferromagnetic resonance technique to demonstrate spin pumping from a FM layer at resonance through the TI layer and into the FM spin sink.
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Affiliation(s)
- David M Burn
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Jheng-Cyuan Lin
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
| | - Ryuji Fujita
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
| | - Barat Achinuq
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
| | - Joshua Bibby
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
| | - Angadjit Singh
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
| | - Andreas Frisk
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Gerrit van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Thorsten Hesjedal
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
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26
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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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27
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Han H, Zhou H, Guillemard C, Valvidares M, Sharma A, Li Y, Sharma AK, Kostanovskiy I, Ernst A, Parkin SSP. Reversal of Anomalous Hall Effect and Octahedral Tilting in SrRuO 3 Thin Films via Hydrogen Spillover. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207246. [PMID: 36271718 DOI: 10.1002/adma.202207246] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/18/2022] [Indexed: 06/16/2023]
Abstract
The perovskite SrRuO3 (SRO) is a strongly correlated oxide whose physical and structural properties are strongly intertwined. Notably, SRO is an itinerant ferromagnet that exhibits a large anomalous Hall effect (AHE) whose sign can be readily modified. Here, a hydrogen spillover method is used to tailor the properties of SRO thin films via hydrogen incorporation. It is found that the magnetization and Curie temperature of the films are strongly reduced and, at the same time, the structure evolves from an orthorhombic to a tetragonal phase as the hydrogen content is increased up to ≈0.9 H per SRO formula unit. The structural phase transition is shown, via in situ crystal truncation rod measurements, to be related to tilting of the RuO6 octahedral units. The significant changes observed in magnetization are shown, via density functional theory (DFT), to be a consequence of shifts in the Fermi level. The reported findings provide new insights into the physical properties of SRO via tailoring its lattice symmetry and emergent physical phenomena via the hydrogen spillover technique.
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Affiliation(s)
- Hyeon Han
- Nano Systems from Ions, Spins, and Electrons (NISE), Max Planck Institute of Microstructure Physics, 06120, Halle (Saale), Germany
| | - Hua Zhou
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Charles Guillemard
- ALBA Synchrotron Light Source, Cerdanyola del Vallès, Barcelona, E-08290, Spain
| | - Manuel Valvidares
- ALBA Synchrotron Light Source, Cerdanyola del Vallès, Barcelona, E-08290, Spain
| | - Arpit Sharma
- Nano Systems from Ions, Spins, and Electrons (NISE), Max Planck Institute of Microstructure Physics, 06120, Halle (Saale), Germany
| | - Yan Li
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Ankit K Sharma
- Nano Systems from Ions, Spins, and Electrons (NISE), Max Planck Institute of Microstructure Physics, 06120, Halle (Saale), Germany
| | - Ilya Kostanovskiy
- Nano Systems from Ions, Spins, and Electrons (NISE), Max Planck Institute of Microstructure Physics, 06120, Halle (Saale), Germany
| | - Arthur Ernst
- Nano Systems from Ions, Spins, and Electrons (NISE), Max Planck Institute of Microstructure Physics, 06120, Halle (Saale), Germany
- Institute for Theoretical Physics, Johannes Kepler University, Linz, 4040, Austria
| | - Stuart S P Parkin
- Nano Systems from Ions, Spins, and Electrons (NISE), Max Planck Institute of Microstructure Physics, 06120, Halle (Saale), Germany
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28
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Vakili H, Ganguly S, de Coster GJ, Neupane MR, Ghosh AW. Low Power In-Memory Computation with Reciprocal Ferromagnet/Topological Insulator Heterostructures. ACS NANO 2022; 16:20222-20228. [PMID: 36459145 PMCID: PMC9798907 DOI: 10.1021/acsnano.2c05645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 11/29/2022] [Indexed: 06/17/2023]
Abstract
The surface state of a 3D topological insulator (3DTI) is a spin-momentum locked conductive state, whose large spin hall angle can be used for the energy-efficient spin-orbit torque based switching of an overlying ferromagnet (FM). Conversely, the gated switching of the magnetization of a separate FM in or out of the TI surface plane can turn on and off the TI surface current. By exploiting this reciprocal behavior, we can use two FM/3DTI heterostructures to design an integrated 1-transistor 1-magnetic tunnel junction random access memory unit (1T1MTJ RAM) for an ultra low power Processing-in-Memory (PiM) architecture. Our calculation involves combining the Fokker-Planck equation with the Nonequilibrium Green Function (NEGF) based flow of conduction electrons and Landau-Lifshitz-Gilbert (LLG) based dynamics of magnetization. Our combined approach allows us to connect device performance metrics with underlying material parameters, which can guide proposed experimental and fabrication efforts.
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Affiliation(s)
- Hamed Vakili
- Department
of Physics, University of Virginia, Charlottesville, Virginia22904, United States
| | - Samiran Ganguly
- Department
of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia22904, United States
- Department
of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, Virginia23284, United States
| | - George J. de Coster
- DEVCOM
Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland20783, United
States
| | - Mahesh R. Neupane
- DEVCOM
Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland20783, United
States
- Materials
Science and Engineering Program, University
of California, Riverside, California92521, United States
| | - Avik W. Ghosh
- Department
of Physics, University of Virginia, Charlottesville, Virginia22904, United States
- Department
of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia22904, United States
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29
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Yu R, Cao JF, Meng XY, Zhu FY, Li JQ, Qu GX, Huang YB, Wang Y, Tai RZ. Highly Tunable Charge-Spin Conversion in Topological Insulator Cr 0.08-(Bi 0.37Sb 0.63) 1.92Te 3 via Ferroelectric Polarization. ACS APPLIED MATERIALS & INTERFACES 2022; 14:48171-48178. [PMID: 36251523 DOI: 10.1021/acsami.2c09778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Topological insulators possess strong spin-orbit coupling, which potentially presents efficient charge-spin interconversion. The effective manipulation of this conversion plays a central role in spin-based device applications and is attracting increasing attention nowadays. In this study, by constructing a multifunctional hybrid device Cr-BST/Py/PMN-PT and applying spin-torque ferromagnetic resonance measurement, continuously controllable charge-spin conversion efficiency and even the enhancement of its value up to about 450% are realized via regulation of the ferroelectric polarization in the topological insulator Cr-BST. The band structure of Cr-BST characterized by angle-resolved photoelectron spectroscopy measurement presents an apparent Dirac-like state located at the large band gap of the bulk state near the Fermi level, which indicates a surface state-dominated contribution to the charge-spin conversion. Further investigation via density functional theory on the electronic structure of BST verifies that the controllable conversion efficiency dominantly originates from the evolution of the band structure under strain modulation. These findings demonstrate TIs as one of the promising materials for the charge-spin interconversion and its regulation, which are instructive for low-dissipation spintronics devices.
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Affiliation(s)
- Rui Yu
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Jie Feng Cao
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Xiang Yu Meng
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Fang Yuan Zhu
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Jun Qin Li
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Ge Xing Qu
- Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Yao Bo Huang
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Yong Wang
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Ren Zhong Tai
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
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30
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Choi WY, Arango IC, Pham VT, Vaz DC, Yang H, Groen I, Lin CC, Kabir ES, Oguz K, Debashis P, Plombon JJ, Li H, Nikonov DE, Chuvilin A, Hueso LE, Young IA, Casanova F. All-Electrical Spin-to-Charge Conversion in Sputtered Bi xSe 1-x. NANO LETTERS 2022; 22:7992-7999. [PMID: 36162104 DOI: 10.1021/acs.nanolett.2c03429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
One of the major obstacles to realizing spintronic devices such as MESO logic devices is the small signal magnitude used for magnetization readout, making it important to find materials with high spin-to-charge conversion efficiency. Although intermixing at the junction of two materials is a widely occurring phenomenon, its influence on material characterization and the estimation of spin-to-charge conversion efficiencies are easily neglected or underestimated. Here, we demonstrate all-electrical spin-to-charge conversion in BixSe1-x nanodevices and show how the conversion efficiency can be overestimated by tens of times depending on the adjacent metal used as a contact. We attribute this to the intermixing-induced compositional change and the properties of a polycrystal that lead to drastic changes in resistivity and spin Hall angle. Strategies to improve the spin-to-charge conversion signal in similar structures for functional devices are discussed.
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Affiliation(s)
- Won Young Choi
- CIC nanoGUNE BRTA, 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Isabel C Arango
- CIC nanoGUNE BRTA, 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Van Tuong Pham
- Univ. Grenoble Alpes, CNRS, Institut Neel, F-38000 Grenoble, France
| | - Diogo C Vaz
- CIC nanoGUNE BRTA, 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Haozhe Yang
- CIC nanoGUNE BRTA, 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Inge Groen
- CIC nanoGUNE BRTA, 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Chia-Ching Lin
- Components Research, Intel Corp., Hillsboro, Oregon 97124, United States
| | - Emily S Kabir
- Components Research, Intel Corp., Hillsboro, Oregon 97124, United States
| | - Kaan Oguz
- Components Research, Intel Corp., Hillsboro, Oregon 97124, United States
| | | | - John J Plombon
- Components Research, Intel Corp., Hillsboro, Oregon 97124, United States
| | - Hai Li
- Components Research, Intel Corp., Hillsboro, Oregon 97124, United States
| | - Dmitri E Nikonov
- Components Research, Intel Corp., Hillsboro, Oregon 97124, United States
| | - Andrey Chuvilin
- CIC nanoGUNE BRTA, 20018 Donostia-San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Basque Country, Spain
| | - Luis E Hueso
- CIC nanoGUNE BRTA, 20018 Donostia-San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Basque Country, Spain
| | - Ian A Young
- Components Research, Intel Corp., Hillsboro, Oregon 97124, United States
| | - Fèlix Casanova
- CIC nanoGUNE BRTA, 20018 Donostia-San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Basque Country, Spain
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31
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Li Y, Zha X, Zhao Y, Lu Q, Li B, Li C, Zhou Z, Liu M. Enhancing the Spin-Orbit Torque Efficiency by the Insertion of a Sub-nanometer β-W Layer. ACS NANO 2022; 16:11852-11861. [PMID: 35912431 DOI: 10.1021/acsnano.2c00093] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Spin-orbit torque (SOT) efficiency is one of the key issues of spintronics. However, enhancing the SOT efficiency is usually limited by the positive correlation between resistivity and the spin Hall ratio, where a high resistivity often accompanies a large spin Hall ratio. Here, we demonstrate that sub-nanometer β-W intercalation has a considerable impact on the SOT efficiency in α-W (6 nm)/Co (8 nm)/Pt (3 nm) samples. The damping-like SOT efficiency per unit current density, ξDLj, of α-W (5.7 nm)/β-W (0.3 nm)/Co (8 nm)/Pt (3 nm) shows a ∼ 296% enhancement compared to that of the α-W/Co/Pt system. Meanwhile, a resistivity similar to that of α-W and the spin Hall ratio larger than β-W induce a giant damping-like SOT efficiency per applied electric field, ξDLE, which is about 12.1 times larger than that of β-W. Our findings will benefit the SOT devices by reducing energy consumption.
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Affiliation(s)
- Yaojin Li
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronics and Information Engineering, the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Xi Zha
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronics and Information Engineering, the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Yifan Zhao
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronics and Information Engineering, the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Qi Lu
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronics and Information Engineering, the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Boyan Li
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronics and Information Engineering, the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Chunlei Li
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronics and Information 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 Electronics and Information Engineering, 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 Electronics and Information Engineering, the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an 710049, China
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32
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Xie Q, Lin W, Liang J, Zhou H, Waqar M, Lin M, Teo SL, Chen H, Lu X, Shu X, Liu L, Chen S, Zhou C, Chai J, Yang P, Loh KP, Wang J, Jiang W, Manchon A, Yang H, Chen J. Rashba-Edelstein Effect in the h-BN Van Der Waals Interface for Magnetization Switching. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109449. [PMID: 35751473 DOI: 10.1002/adma.202109449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Van der Waals materials are attracting great attention in the field of spintronics due to their novel physical properties. For example, they are utilized as spin-current generating materials in spin-orbit torque (SOT) devices, which offers an electrical way to control the magnetic state and is promising for future low-power electronics. However, SOTs have mostly been demonstrated in vdW materials with strong spin-orbit coupling (SOC). Here, the observation of a current-induced SOT in the h-BN/SrRuO3 bilayer structure is reported, where the vdW material (h-BN) is an insulator with negligible SOC. Importantly, this SOT is strong enough to induce the switching of the perpendicular magnetization in SrRuO3 . First-principles calculations suggest a giant Rashba effect at the interface between vdW material and SrRuO3 (110)pc thin film, which leads to the observed SOT based on a simplified tight-binding model. Furthermore, it is demonstrated that the current-induced magnetization switching can be modulated by the electric field. This study paves the way for exploring the current-induced SOT and magnetization switching by integrating vdW materials with ferromagnets.
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Affiliation(s)
- Qidong Xie
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Weinan Lin
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
- Department of physics, Xiamen University, Xiamen, 361005, China
| | - Jinghua Liang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hengan Zhou
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Moaz Waqar
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, 119077, Singapore
| | - Ming Lin
- Institute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore
| | - Siew Lang Teo
- Institute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore
| | - Hao Chen
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Xiufang Lu
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Xinyu Shu
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Liang Liu
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Shaohai Chen
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Chenghang Zhou
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Jianwei Chai
- Institute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore
| | - Ping Yang
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - Kian Ping Loh
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - John Wang
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Wanjun Jiang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China
| | | | - Hongxin Yang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jingsheng Chen
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore
- Institute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), 2 Fusionopolis Way, Innovis, #08-03, Singapore, 138634, Singapore
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33
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Zhang Y, Kalappattil V, Liu C, Mehraeen M, Zhang SSL, Ding J, Erugu U, Chen Z, Tian J, Liu K, Tang J, Wu M. Large magnetoelectric resistance in the topological Dirac semimetal α-Sn. SCIENCE ADVANCES 2022; 8:eabo0052. [PMID: 35905193 PMCID: PMC9337753 DOI: 10.1126/sciadv.abo0052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
The spin-momentum locking of surface states in topological materials can produce a resistance that scales linearly with magnetic and electric fields. Such a bilinear magnetoelectric resistance (BMER) effect offers a new approach for information reading and field sensing applications, but the effects demonstrated so far are too weak or for low temperatures. This article reports the first observation of BMER effects in topological Dirac semimetals; the BMER responses were measured at room temperature and were substantially stronger than those reported previously. The experiments used topological Dirac semimetal α-Sn thin films grown on silicon substrates. The films showed BMER responses that are 106 times larger than previously measured at room temperature and are also larger than those previously obtained at low temperatures. These results represent a major advance toward realistic BMER applications. Significantly, the data also yield the first characterization of three-dimensional Fermi-level spin texture of topological surface states in α-Sn.
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Affiliation(s)
- Yuejie Zhang
- Department of Physics, Colorado State University, Fort Collins, CO 80523, USA
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | | | - Chuanpu Liu
- Department of Physics, Colorado State University, Fort Collins, CO 80523, USA
| | - M. Mehraeen
- Department of Physics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Steven S.-L. Zhang
- Department of Physics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Jinjun Ding
- Department of Physics, Colorado State University, Fort Collins, CO 80523, USA
| | - Uppalaiah Erugu
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071, USA
| | - Zhijie Chen
- Physics Department, Georgetown University, Washington, DC 20057, USA
| | - Jifa Tian
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071, USA
| | - Kai Liu
- Physics Department, Georgetown University, Washington, DC 20057, USA
| | - Jinke Tang
- Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071, USA
| | - Mingzhong Wu
- Department of Physics, Colorado State University, Fort Collins, CO 80523, USA
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34
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Li CH, Moon J, van 't Erve OMJ, Wickramaratne D, Cobas ED, Johannes MD, Jonker BT. Spin-Sensitive Epitaxial In 2Se 3 Tunnel Barrier in In 2Se 3/Bi 2Se 3 Topological van der Waals Heterostructure. ACS APPLIED MATERIALS & INTERFACES 2022; 14:34093-34100. [PMID: 35820066 DOI: 10.1021/acsami.2c08053] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Current-generated spin arising from spin-momentum locking in topological insulator (TI) surface states has been shown to switch the magnetization of an adjacent ferromagnet (FM) via spin-orbit torque (SOT) with a much higher efficiency than heavy metals. However, in such FM/TI heterostructures, most of the current is shunted through the FM metal due to its lower resistance, and recent calculations have also shown that topological surface states can be significantly impacted when interfaced with an FM metal such as Ni and Co. Hence, placing an insulating layer between the TI and FM will not only prevent current shunting, therefore minimizing overall power consumption, but may also help preserve the topological surface states at the interface. Here, we report the van der Waals epitaxial growth of β-phase In2Se3 on Bi2Se3 by molecular beam epitaxy and demonstrate its spin sensitivity by the electrical detection of current-generated spin in Bi2Se3 surface states using a Fe/In2Se3 detector contact. Our density functional calculations further confirm that the linear dispersion and spin texture of the Bi2Se3 surface states are indeed preserved at the In2Se3/Bi2Se3 interface. This demonstration of an epitaxial crystalline spin-sensitive barrier that can be grown directly on Bi2Se3, and verification that it preserves the topological surface state, is electrically insulating and spin-sensitive, is an important step toward minimizing overall power consumption in SOT switching in TI/FM heterostructures in fully epitaxial topological spintronic devices.
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Affiliation(s)
- Connie H Li
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Jisoo Moon
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
- National Research Council, Washington, DC 20001, United States
| | - Olaf M J van 't Erve
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Darshana Wickramaratne
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Enrique D Cobas
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Michelle D Johannes
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Berend T Jonker
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
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35
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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: 10] [Impact Index Per Article: 5.0] [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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36
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Ning S, Liu H, Wu J, Luo F. Challenges and opportunities for spintronics based on spin orbit torque. FUNDAMENTAL RESEARCH 2022; 2:535-538. [PMID: 38933998 PMCID: PMC11197755 DOI: 10.1016/j.fmre.2022.05.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 04/26/2022] [Accepted: 05/15/2022] [Indexed: 11/28/2022] Open
Abstract
Spintronic devices based on spin orbit torque (SOT) have become the most promising pathway to the next-generation of ultralow-power nonvolatile logic and memory applications. Typical SOT-based spintronic devices consist of two functional materials: a spin source and a magnetic material. Spin source materials possess a strong spin orbit coupling, enabling efficient interconversion between charge and spin current. Magnetic materials are used to process and archive the information via the interaction between the local magnetic moment and the spin current generated from spin source. Considerable efforts have been put into the design of materials and devices in the past decades to realize the electrical control of magnetic switching. However, a number of key challenges still remain to be addressed for the practical application. In this paper, we reviewed the development of a range of novel materials for both the spin source and the magnetic functionalities, particularly the complex oxides and organic spintronic materials. We also discussed and highlighted several key issues, such as the mechanism and manipulation of SOT and the large-scale integration of SOT-based devices, which merit more attention in the future.
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Affiliation(s)
- Shuai Ning
- School of Materials Science and Engineering, Nankai University, Tianjin 300350, China
| | - Haoliang Liu
- School of Science, Harbin Institute of Technology, Shenzhen 518055, China
| | - Jingxiong Wu
- School of Materials Science and Engineering, Nankai University, Tianjin 300350, China
| | - Feng Luo
- School of Materials Science and Engineering, Nankai University, Tianjin 300350, China
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Park H, Rho S, Kim J, Kim H, Kim D, Kang C, Cho M. Topological Surface-Dominated Spintronic THz Emission in Topologically Nontrivial Bi 1- x Sb x Films. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2200948. [PMID: 35596613 PMCID: PMC9313944 DOI: 10.1002/advs.202200948] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/12/2022] [Indexed: 05/13/2023]
Abstract
Topological materials have significant potential for spintronic applications owing to their superior spin-charge interconversion. Here, the spin-to-charge conversion (SCC) characteristics of epitaxial Bi1- x Sbx films is investigated across the topological phase transition by spintronic terahertz (THz) spectroscopy. An unexpected, intense spintronic THz emission is observed in the topologically nontrivial semimetal Bi1- x Sbx films, significantly greater than that of Pt and Bi2 Se3 , which indicates the potential of Bi1- x Sbx for spintronic applications. More importantly, the topological surface state (TSS) is observed to significantly contribute to SCC, despite the coexistence of the bulk state, which is possible via a unique ultrafast SCC process, considering the decay process of the spin-polarized hot electrons. This means that topological material-based spintronic devices should be fabricated in a manner that fully utilizes the TSS, not the bulk state, to maximize their performance. The results not only provide a clue for identifying the source of the giant spin Hall angle of Bi1- x Sbx , but also expand the application potential of topological materials by indicating that the optically induced spin current provides a unique method for focused-spin injection into the TSS.
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Affiliation(s)
- Hanbum Park
- Department of PhysicsYonsei UniversitySeoul03722Republic of Korea
- Department of Electrical and Computer EngineeringNational University of SingaporeSingapore119260Singapore
| | - Seungwon Rho
- Department of PhysicsYonsei UniversitySeoul03722Republic of Korea
| | - Jonghoon Kim
- Department of PhysicsYonsei UniversitySeoul03722Republic of Korea
| | - Hyeongmun Kim
- Department of PhysicsChonnam National UniversityGwangju61186Republic of Korea
- Advanced Photonics Research InstituteGwangju Institute of Science and TechnologyGwangju61005Republic of Korea
| | - Dajung Kim
- Department of PhysicsYonsei UniversitySeoul03722Republic of Korea
| | - Chul Kang
- Advanced Photonics Research InstituteGwangju Institute of Science and TechnologyGwangju61005Republic of Korea
| | - Mann‐Ho Cho
- Department of PhysicsYonsei UniversitySeoul03722Republic of Korea
- Department of System Semiconductor EngineeringYonsei UniversitySeoul03722Republic of Korea
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Wang P, Migliorini A, Yang SH, Jeon JC, Kostanovskiy I, Meyerheim H, Han H, Deniz H, Parkin SSP. Giant Spin Hall Effect and Spin-Orbit Torques in 5d Transition Metal-Aluminum Alloys from Extrinsic Scattering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109406. [PMID: 35365874 DOI: 10.1002/adma.202109406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 03/22/2022] [Indexed: 06/14/2023]
Abstract
The generation of spin currents from charge currents via the spin Hall effect (SHE) is of fundamental and technological interest. Here, some of the largest SHEs yet observed via extrinsic scattering are found in a large class of binary compounds formed from a 5d element and aluminum, with a giant spin Hall angle (SHA) of ≈1 in the compound Os22 Al78 . A critical composition of the 5d element is found at which there is a structural phase boundary between poorly and highly textured crystalline material, where the SHA exhibits its largest value. Furthermore, a systematic increase is found in the spin Hall conductivity (SHC) and SHA at this critical composition as the atomic number of the 5d element is systematically increased. This clearly shows that the SHE and SHC are derived from extrinsic scattering mechanisms related to the potential mismatch between the 5d element and Al. These studies show the importance of extrinsic mechanisms derived from potential mismatch as a route to obtaining large spin Hall angles with high technological impact. Indeed, it is demonstrated that a state-of-the-art racetrack device has a several-fold increased current-induced domain wall efficiency using these materials as compared to prior-art materials.
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Affiliation(s)
- Peng Wang
- Max Planck Institute for Microstructure Physics, 06120, Halle, Germany
- Institute of Physics, Martin Luther University Halle-Wittenberg, 06120, Halle, Germany
| | - Andrea Migliorini
- Max Planck Institute for Microstructure Physics, 06120, Halle, Germany
| | - See-Hun Yang
- Max Planck Institute for Microstructure Physics, 06120, Halle, Germany
| | - Jae-Chun Jeon
- Max Planck Institute for Microstructure Physics, 06120, Halle, Germany
| | - Ilya Kostanovskiy
- Max Planck Institute for Microstructure Physics, 06120, Halle, Germany
| | - Holger Meyerheim
- Max Planck Institute for Microstructure Physics, 06120, Halle, Germany
| | - Hyeon Han
- Max Planck Institute for Microstructure Physics, 06120, Halle, Germany
| | - Hakan Deniz
- Max Planck Institute for Microstructure Physics, 06120, Halle, Germany
| | - Stuart S P Parkin
- Max Planck Institute for Microstructure Physics, 06120, Halle, Germany
- Institute of Physics, Martin Luther University Halle-Wittenberg, 06120, Halle, Germany
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Wu B, Jin M, Luo Y, Xu X, Fan H, Huang H, Feng Z, Zhuang Y, Yu C, Zhou T. Enhancement of Damping-Like Field and Field-Free Switching in Pt/(Co/Pt)/PtMn Trilayer Films Prepared in the Presence of an In Situ Magnetic Field. ACS APPLIED MATERIALS & INTERFACES 2022; 14:21668-21676. [PMID: 35471960 DOI: 10.1021/acsami.2c02621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The current-induced magnetization switching and damping-like field in Pt/(Co/Pt)/PtMn trilayer films prepared with and without an in situ in-plane field of 600 Oe have been studied systematically. In the presence of the in situ field, a small in-plane bias field (HEB) is observed for films with PtMn thickness ≥5 nm, while there is no observable HEB for PtMn thickness ≤3 nm. Nevertheless, a field-free switching of perpendicular magnetization of Co/Pt is observed for all the films with the PtMn thickness of 1-7 nm. On the other hand, without the presence of the in situ field, HEB and field-free switching are not seen. Furthermore, the damping-like fields (HDL) are much enhanced in the presence of the in situ field, and the increasement can be up to 47%. We further revealed that the spin current is mainly from the Pt layer, while the noncollinear spin configuration at the interface caused by the in situ in-plane field may play a role in the HDL enhancement. Micromagnetic simulations indicate that the canting of antiferromagnet PtMn spins plays an important role in the field-free switching. Our findings clarify the source of spin current in the trilayer films and provide an easier approach to field-free switching and HDL enhancement for future low-power spintronic devices.
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Affiliation(s)
- Birui Wu
- School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018, China
- College of Information and Mechanical Electrical Engineering, Ningde Normal University, Ningde 352100, China
| | - Menghao Jin
- School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018, China
| | - Yongming Luo
- School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018, China
| | - Xiuyuan Xu
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L3 8LG, UK
| | - Haodong Fan
- School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018, China
| | - Haixia Huang
- School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018, China
| | - Zhongshu Feng
- School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018, China
| | - Yanshan Zhuang
- School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018, China
| | - Changqiu Yu
- School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018, China
| | - Tiejun Zhou
- School of Electronics and Information Engineering, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018, China
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40
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Xu X, Zhang D, Liu B, Meng H, Xu J, Zhong Z, Tang X, Zhang H, Jin L. Giant Extrinsic Spin Hall Effect in Platinum-Titanium Oxide Nanocomposite Films. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105726. [PMID: 35393788 PMCID: PMC9165503 DOI: 10.1002/advs.202105726] [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: 12/09/2021] [Revised: 03/05/2022] [Indexed: 06/14/2023]
Abstract
Although the spin Hall effect provides a pathway for efficient and fast current-induced manipulation of magnetization, application of spin-orbit torque magnetic random access memory with low power dissipation is still limited to spin Hall materials with low spin Hall angles or very high resistivities. This work reports a group of spin Hall materials, Pt1 -x (TiO2 )x nanocomposites, that combines a giant spin Hall effect with a low resistivity. The spin Hall angle of Pt1 -x (TiO2 )x in an yttrium iron garnet/Pt1 -x (TiO2 )x double-layer heterostructure is estimated from a combination of ferromagnetic resonance, spin pumping, and inverse spin Hall experiments. A giant spin Hall angle 1.607 ± 0.04 is obtained in a Pt0.94 (TiO2 )0.06 nanocomposite film, which is an increase by an order of magnitude compared with 0.051 ± 0.002 in pure Pt thin film under the same conditions. The great enhancement of spin Hall angle is attributed to strong side-jump induced by TiO2 impurities. These findings provide a new nanocomposite spin Hall material combining a giant spin Hall angle, low resistivity and excellent process compatibility with semiconductors for developing highly efficiency current-induced magnetization switching memory devices and logic devices.
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Affiliation(s)
- Xinkai Xu
- State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of ChinaChengdu610054China
| | - Dainan Zhang
- State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of ChinaChengdu610054China
| | - Bo Liu
- Key Laboratory of Spintronics MaterialsDevices and Systems of Zhejiang ProvinceHangzhou311305China
| | - Hao Meng
- Key Laboratory of Spintronics MaterialsDevices and Systems of Zhejiang ProvinceHangzhou311305China
| | - Jiapeng Xu
- State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of ChinaChengdu610054China
| | - Zhiyong Zhong
- State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of ChinaChengdu610054China
| | - Xiaoli Tang
- State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of ChinaChengdu610054China
| | - Huaiwu Zhang
- State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of ChinaChengdu610054China
| | - Lichuan Jin
- State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of ChinaChengdu610054China
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41
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Bhattacharjee N, Mahalingam K, Fedorko A, Lauter V, Matzelle M, Singh B, Grutter A, Will-Cole A, Page M, McConney M, Markiewicz R, Bansil A, Heiman D, Sun NX. Topological Antiferromagnetic Van der Waals Phase in Topological Insulator/Ferromagnet Heterostructures Synthesized by a CMOS-Compatible Sputtering Technique. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108790. [PMID: 35132680 DOI: 10.1002/adma.202108790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/30/2022] [Indexed: 06/14/2023]
Abstract
Breaking time-reversal symmetry by introducing magnetic order, thereby opening a gap in the topological surface state bands, is essential for realizing useful topological properties such as the quantum anomalous Hall and axion insulator states. In this work, a novel topological antiferromagnetic (AFM) phase is created at the interface of a sputtered, c-axis-oriented, topological insulator/ferromagnet heterostructure-Bi2 Te3 /Ni80 Fe20 because of diffusion of Ni in Bi2 Te3 (Ni-Bi2 Te3 ). The AFM property of the Ni-Bi2 Te3 interfacial layer is established by observation of spontaneous exchange bias in the magnetic hysteresis loop and compensated moments in the depth profile of the magnetization using polarized neutron reflectometry. Analysis of the structural and chemical properties of the Ni-Bi2 Te3 layer is carried out using selected-area electron diffraction, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy. These studies, in parallel with first-principles calculations, indicate a solid-state chemical reaction that leads to the formation of Ni-Te bonds and the presence of topological antiferromagnetic (AFM) compound NiBi2 Te4 in the Ni-Bi2 Te3 interface layer. The Neél temperature of the Ni-Bi2 Te3 layer is ≈63 K, which is higher than that of typical magnetic topological insulators (MTIs). The presented results provide a pathway toward industrial complementary metal-oxide-semiconductor (CMOS)-process-compatible sputtered-MTI heterostructures, leading to novel materials for topological quantum devices.
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Affiliation(s)
- Nirjhar Bhattacharjee
- Northeastern University, Department of Electrical and Computer Engineering, Boston, MA, 02115, USA
| | - Krishnamurthy Mahalingam
- Air Force Research Laboratory, Nano-electronic Materials Branch, Wright Patterson Air Force Base, Boston, OH, 05433, USA
| | - Adrian Fedorko
- Northeastern University, Department of Physics, Boston, MA, 02115, USA
| | - Valeria Lauter
- Quantum Condensed Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Boston, TN, 37831, USA
| | - Matthew Matzelle
- Northeastern University, Department of Physics, Boston, MA, 02115, USA
| | - Bahadur Singh
- Tata Institute of Fundamental Research, Department of Condensed Matter Physics and Materials Science, Mumbai, 400005, India
| | - Alexander Grutter
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Alexandria Will-Cole
- Northeastern University, Department of Electrical and Computer Engineering, Boston, MA, 02115, USA
| | - Michael Page
- Air Force Research Laboratory, Nano-electronic Materials Branch, Wright Patterson Air Force Base, Boston, OH, 05433, USA
| | - Michael McConney
- Air Force Research Laboratory, Nano-electronic Materials Branch, Wright Patterson Air Force Base, Boston, OH, 05433, USA
| | - Robert Markiewicz
- Northeastern University, Department of Physics, Boston, MA, 02115, USA
| | - Arun Bansil
- Northeastern University, Department of Physics, Boston, MA, 02115, USA
| | - Don Heiman
- Northeastern University, Department of Physics, Boston, MA, 02115, USA
- Plasma Science and Fusion Center, MIT, Cambridge, MA, 02139, USA
| | - Nian Xiang Sun
- Northeastern University, Department of Electrical and Computer Engineering, Boston, MA, 02115, USA
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42
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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: 7] [Impact Index Per Article: 3.5] [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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43
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Improved spin-orbit torque induced magnetization switching efficiency by helium ion irradiation. Sci Rep 2022; 12:3465. [PMID: 35236883 PMCID: PMC8891290 DOI: 10.1038/s41598-022-06960-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 02/02/2022] [Indexed: 12/02/2022] Open
Abstract
Increasing the efficiency of spin–orbit torque (SOT) is of great interest in spintronics devices because of its application to the non-volatile magnetic random access memory and in-logic memory devices. Accordingly, there are several studies to alter the magnetic properties and reduce the SOT switching current with helium ion irradiation, but previous researches are focused on its phenomenological changes only. Here, the authors observe the reduction of switching current and analyze its origins. The analyzed major reasons are improved spin Hall angle represented as the changed resistivity of heavy metal layer and the reduction of surface anisotropy energy at interface between heavy metal and ferromagnet. It is confirmed that almost linear relation between changed SHA and Pt resistivity by helium ion irradiation, which is attributed because of the increase in the scattering sources induced by structural distortion during ion penetration. From the calculated power consumption ratio based on the derived parameter, the requiring power decreases according to the degree of ion irradiation. Our results show that helium ion penetration induced layer and interfacial disturbance affects SOT induced magnetization switching current reduction and may provide possibility about helium ion irradiation based superior SOT device engineering.
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44
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Fan T, Khang NHD, Nakano S, Hai PN. Ultrahigh efficient spin orbit torque magnetization switching in fully sputtered topological insulator and ferromagnet multilayers. Sci Rep 2022; 12:2998. [PMID: 35194059 PMCID: PMC8863830 DOI: 10.1038/s41598-022-06779-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 02/07/2022] [Indexed: 11/09/2022] Open
Abstract
Spin orbit torque (SOT) magnetization switching of ferromagnets with large perpendicular magnetic anisotropy has a great potential for the next generation non-volatile magnetoresistive random-access memory (MRAM). It requires a high performance pure spin current source with a large spin Hall angle and high electrical conductivity, which can be fabricated by a mass production technique. In this work, we demonstrate ultrahigh efficient and robust SOT magnetization switching in fully sputtered BiSb topological insulator and perpendicularly magnetized Co/Pt multilayers. Despite fabricated by the magnetron sputtering instead of the laboratory molecular beam epitaxy, the topological insulator layer, BiSb, shows a large spin Hall angle of θSH = 10.7 and high electrical conductivity of σ = 1.5 × 105 Ω-1 m-1. Our results demonstrate the feasibility of BiSb topological insulator for implementation of ultralow power SOT-MRAM and other SOT-based spintronic devices.
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Affiliation(s)
- Tuo Fan
- Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8550, Japan
| | - Nguyen Huynh Duy Khang
- Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8550, Japan
- Department of Physics, Ho Chi Minh City University of Education, 280 An Duong Vuong Street, District 5, Ho Chi Minh City, 738242, Vietnam
| | - Soichiro Nakano
- Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8550, Japan
| | - Pham Nam Hai
- Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8550, Japan.
- Center for Spintronics Research Network (CSRN), The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656, Japan.
- CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
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45
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Efficient spin current source using a half-Heusler alloy topological semimetal with back end of line compatibility. Sci Rep 2022; 12:2426. [PMID: 35165335 PMCID: PMC8844406 DOI: 10.1038/s41598-022-06325-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/27/2022] [Indexed: 11/16/2022] Open
Abstract
Topological materials, such as topological insulators (TIs), have great potential for ultralow power spintronic devices, thanks to their giant spin Hall effect. However, the giant spin Hall angle (θSH > 1) is limited to a few chalcogenide TIs with toxic elements and low melting points, making them challenging for device integration during the silicon Back-End-of-Line (BEOL) process. Here, we show that by using a half-Heusler alloy topological semi-metal (HHA-TSM), YPtBi, it is possible to achieve both a giant θSH up to 4.1 and a high thermal budget up to 600 °C. We demonstrate magnetization switching of a CoPt thin film using the giant spin Hall effect of YPtBi by current densities lower than those of heavy metals by one order of magnitude. Since HHA-TSM includes a group of three-element topological materials with great flexibility, our work opens the door to the third-generation spin Hall materials with both high θSH and high compatibility with the BEOL process that would be easily adopted by the industry.
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46
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Ding S, Liang Z, Go D, Yun C, Xue M, Liu Z, Becker S, Yang W, Du H, Wang C, Yang Y, Jakob G, Kläui M, Mokrousov Y, Yang J. Observation of the Orbital Rashba-Edelstein Magnetoresistance. PHYSICAL REVIEW LETTERS 2022; 128:067201. [PMID: 35213174 DOI: 10.1103/physrevlett.128.067201] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 12/06/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
We report the observation of magnetoresistance (MR) that could originate from the orbital angular momentum (OAM) transport in a permalloy (Py)/oxidized Cu (Cu^{*}) heterostructure: the orbital Rashba-Edelstein magnetoresistance. The angular dependence of the MR depends on the relative angle between the induced OAM and the magnetization in a similar fashion as the spin Hall magnetoresistance. Despite the absence of elements with large spin-orbit coupling, we find a sizable MR ratio, which is in contrast to the conventional spin Hall magnetoresistance which requires heavy elements. Through Py thickness-dependence studies, we conclude another mechanism beyond the conventional spin-based scenario is responsible for the MR observed in Py/Cu^{*} structures-originated in a sizable transport of OAM. Our findings not only suggest the current-induced torques without using any heavy elements via the OAM channel but also provide an important clue towards the microscopic understanding of the role that OAM transport can play for magnetization dynamics.
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Affiliation(s)
- Shilei Ding
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Zhongyu Liang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Dongwook Go
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
- Institute of Physics, Johannes Gutenberg-University Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Chao Yun
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Mingzhu Xue
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Zhou Liu
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Sven Becker
- Institute of Physics, Johannes Gutenberg-University Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Wenyun Yang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Honglin Du
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Changsheng Wang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Yingchang Yang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Gerhard Jakob
- Institute of Physics, Johannes Gutenberg-University Mainz, Staudingerweg 7, 55128 Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, 55128 Mainz, Germany
| | - Mathias Kläui
- Institute of Physics, Johannes Gutenberg-University Mainz, Staudingerweg 7, 55128 Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, 55128 Mainz, Germany
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Yuriy Mokrousov
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
- Institute of Physics, Johannes Gutenberg-University Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Jinbo Yang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
- Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing 100871, People's Republic of China
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47
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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: 32] [Impact Index Per Article: 16.0] [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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48
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He QL, Hughes TL, Armitage NP, Tokura Y, Wang KL. Topological spintronics and magnetoelectronics. NATURE MATERIALS 2022; 21:15-23. [PMID: 34949869 DOI: 10.1038/s41563-021-01138-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 09/21/2021] [Indexed: 05/08/2023]
Abstract
Topological electronic materials, such as topological insulators, are distinct from trivial materials in the topology of their electronic band structures that lead to robust, unconventional topological states, which could bring revolutionary developments in electronics. This Perspective summarizes developments of topological insulators in various electronic applications including spintronics and magnetoelectronics. We group and analyse several important phenomena in spintronics using topological insulators, including spin-orbit torque, the magnetic proximity effect, interplay between antiferromagnetism and topology, and the formation of topological spin textures. We also outline recent developments in magnetoelectronics such as the axion insulator and the topological magnetoelectric effect observed using different topological insulators.
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Affiliation(s)
- Qing Lin He
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.
- Collaborative Innovation Center of Quantum Matter, Beijing, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China.
| | - Taylor L Hughes
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - N Peter Armitage
- Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD, USA
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
- Tokyo College, University of Tokyo, Tokyo, Japan
| | - Kang L Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA, USA.
- Center of Quantum Sciences and Engineering, University of California, Los Angeles, CA, USA.
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49
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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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50
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Liu J, Hesjedal T. Magnetic Topological Insulator Heterostructures: A Review. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021:e2102427. [PMID: 34665482 DOI: 10.1002/adma.202102427] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/05/2021] [Indexed: 06/13/2023]
Abstract
Topological insulators (TIs) provide intriguing prospects for the future of spintronics due to their large spin-orbit coupling and dissipationless, counter-propagating conduction channels in the surface state. The combination of topological properties and magnetic order can lead to new quantum states including the quantum anomalous Hall effect that was first experimentally realized in Cr-doped (Bi,Sb)2 Te3 films. Since magnetic doping can introduce detrimental effects, requiring very low operational temperatures, alternative approaches are explored. Proximity coupling to magnetically ordered systems is an obvious option, with the prospect to raise the temperature for observing the various quantum effects. Here, an overview of proximity coupling and interfacial effects in TI heterostructures is presented, which provides a versatile materials platform for tuning the magnetic and topological properties of these exciting materials. An introduction is first given to the heterostructure growth by molecular beam epitaxy and suitable structural, electronic, and magnetic characterization techniques. Going beyond transition-metal-doped and undoped TI heterostructures, examples of heterostructures are discussed, including rare-earth-doped TIs, magnetic insulators, and antiferromagnets, which lead to exotic phenomena such as skyrmions and exchange bias. Finally, an outlook on novel heterostructures such as intrinsic magnetic TIs and systems including 2D materials is given.
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Affiliation(s)
- Jieyi Liu
- Clarendon Laboratory, Department of Physics University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Thorsten Hesjedal
- Clarendon Laboratory, Department of Physics University of Oxford, Parks Road, Oxford, OX1 3PU, UK
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