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Xiang X, Xu J, Zhang Z, Jiang S, Wang Y, Wu B, Wang W, Hou X, Xu G, Zhao X, Gao N, Long S. An Antiferromagnetic Neuromorphic Memory Based on Perpendicularly Magnetized CoO. NANO LETTERS 2024; 24:11187-11193. [PMID: 39141575 DOI: 10.1021/acs.nanolett.4c02340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/16/2024]
Abstract
Antiferromagnets (AFMs) are ideal materials to boost neuromorphic computing toward the ultrahigh speed and ultracompact integration regime. However, developing a suitable AFM neuromorphic memory remains an aspirational but challenging goal. In this work, we construct such a memory based on the CoO/Pt heterostructure, in which the collinear insulating AFM CoO shows a strong perpendicular anisotropy facilitating its electrical readout and writing. Utilizing the unique nonlinear response and bipolar fading memory properties of the device, we demonstrate a multidimensional reservoir computing beyond the traditional binary paradigm. These results are expected to pave the way toward next-generation fast and massive neuromorphic computing.
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Affiliation(s)
- Xueqiang Xiang
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
| | - Jiankang Xu
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
| | - Zhongfang Zhang
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
| | - Siyuan Jiang
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
| | - Yalong Wang
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
| | - Biao Wu
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
| | - Wei Wang
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
| | - Xiaohu Hou
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
| | - Guangwei Xu
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
| | - Xiaolong Zhao
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
| | - Nan Gao
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei 230026, China
| | - Shibing Long
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
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2
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Jia Z, Zhao M, Chen Q, Sun R, Cao L, Ye K, Zhu T, Liu L, Tian Y, Wang Y, Du J, Zhang F, Lv W, Ling F, Zhai Y, Jiang Y, Wang Z. Spin Transport Modulation of 2D Fe 3O 4 Nanosheets Driven by Verwey Phase Transition. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2405945. [PMID: 39229956 DOI: 10.1002/advs.202405945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 08/06/2024] [Indexed: 09/05/2024]
Abstract
Realizing spin transport between heavy metal and two-dimensional (2D) magnetic materials at high Curie temperature (TC) is crucial to advanced spintronic information storage technology. Here, environmentally stable 2D nonlayered Fe3O4 nanosheets are successfully synthesized using a reproducible process and found that they exhibit vortex magnetic domains at room temperature. A Verwey phase transition temperature (TV) of ≈110 K is identified for ≈3 nm thick nanosheet through Raman characterization and spin Hall device measurement of the Pt/Fe3O4 bilayer. The anisotropic magnetoresistance ratio decreases near TV, while both the spin Hall magnetoresistance ratio and spin mixing conductance (Gr) increase at TV. As the temperature approaches 112 K, the anomalous Hall effect ratio tends to become zero. The maximum Gr reaches ≈5 × 1015 Ω-1m-2 due to the clean and flat interface between Pt and 2D nanosheet. The observed spin transport behavior in Pt/Fe3O4 spin Hall devices indicates that 2D Fe3O4 nanosheets possess potential for high-power micro spintronic storage devices applications.
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Affiliation(s)
- Zhiyan Jia
- Institute of Quantum Materials and Devices, School of Materials Science and Engineering, Tiangong University, Tianjin, 300387, China
- International Iberian Nanotechnology Laboratory (INL), Braga, 4715-330, Portugal
| | - Mengfan Zhao
- Institute of Quantum Materials and Devices, School of Materials Science and Engineering, Tiangong University, Tianjin, 300387, China
| | - Qian Chen
- Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, 211189, China
- Key Laboratory of Nanodevices and Applications Suzhou Institute of Nano-Tech and Nano-Bionics CAS, Suzhou, 215123, China
| | - Rong Sun
- International Iberian Nanotechnology Laboratory (INL), Braga, 4715-330, Portugal
| | - Lulu Cao
- Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, 211189, China
| | - Kun Ye
- Institute of Quantum Materials and Devices, School of Materials Science and Engineering, Tiangong University, Tianjin, 300387, China
| | - Tao Zhu
- Institute of Quantum Materials and Devices, School of Materials Science and Engineering, Tiangong University, Tianjin, 300387, China
| | - Lixuan Liu
- Institute of Quantum Materials and Devices, School of Materials Science and Engineering, Tiangong University, Tianjin, 300387, China
| | - Yuxin Tian
- Institute of Quantum Materials and Devices, School of Materials Science and Engineering, Tiangong University, Tianjin, 300387, China
| | - Yi Wang
- Institute of Quantum Materials and Devices, School of Materials Science and Engineering, Tiangong University, Tianjin, 300387, China
| | - Jie Du
- Institute of Quantum Materials and Devices, School of Materials Science and Engineering, Tiangong University, Tianjin, 300387, China
| | - Fang Zhang
- Institute of Quantum Materials and Devices, School of Materials Science and Engineering, Tiangong University, Tianjin, 300387, China
| | - Weiming Lv
- Key Laboratory of Nanodevices and Applications Suzhou Institute of Nano-Tech and Nano-Bionics CAS, Suzhou, 215123, China
| | - FeiFei Ling
- School of Electrical and Information Engineering, Tianjin University, Tianjin, 300072, China
- Hebei Technology Innovation Center of Phase Change Thermal Management of Data Center, Hebei University of Water Resources and Electric Engineering, Cangzhou, 061001, China
| | - Ya Zhai
- Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, 211189, China
| | - Yong Jiang
- Institute of Quantum Materials and Devices, School of Materials Science and Engineering, Tiangong University, Tianjin, 300387, China
| | - Zhongchang Wang
- International Iberian Nanotechnology Laboratory (INL), Braga, 4715-330, Portugal
- School of Chemistry, Beihang University, Beijing, 100191, China
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3
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Chen L, Sun Y, Mankovsky S, Meier TNG, Kronseder M, Sun C, Orekhov A, Ebert H, Weiss D, Back CH. Signatures of magnetism control by flow of angular momentum. Nature 2024; 633:548-553. [PMID: 39232172 PMCID: PMC11410660 DOI: 10.1038/s41586-024-07914-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 08/06/2024] [Indexed: 09/06/2024]
Abstract
Exploring new strategies to manipulate the order parameter of magnetic materials by electrical means is of great importance not only for advancing our understanding of fundamental magnetism but also for unlocking potential applications. A well-established concept uses gate voltages to control magnetic properties by modulating the carrier population in a capacitor structure1-5. Here we show that, in Pt/Al/Fe/GaAs(001) multilayers, the application of an in-plane charge current in Pt leads to a shift in the ferromagnetic resonance field depending on the microwave frequency when the Fe film is sufficiently thin. The experimental observation is interpreted as a current-induced modification of the magnetocrystalline anisotropy ΔHA of Fe. We show that (1) ΔHA decreases with increasing Fe film thickness and is connected to the damping-like torque; and (2) ΔHA depends not only on the polarity of charge current but also on the magnetization direction, that is, ΔHA has an opposite sign when the magnetization direction is reversed. The symmetry of the modification is consistent with a current-induced spin6-8 and/or orbit9-13 accumulation, which, respectively, act on the spin and/or orbit component of the magnetization. In this study, as Pt is regarded as a typical spin current source6,14, the spin current can play a dominant part. The control of magnetism by a spin current results from the modified exchange splitting of the majority and minority spin bands, providing functionality that was previously unknown and could be useful in advanced spintronic devices.
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Affiliation(s)
- L Chen
- Department of Physics, Technical University of Munich, Munich, Germany.
| | - Y Sun
- Department of Physics, Technical University of Munich, Munich, Germany
| | - S Mankovsky
- Department of Chemistry, Ludwig Maximilian University, Munich, Germany
| | - T N G Meier
- Department of Physics, Technical University of Munich, Munich, Germany
| | - M Kronseder
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - C Sun
- Department of Chemistry, Technical University of Munich, Munich, Germany
- TUMint.Energy Research, Department of Chemistry, Technical University of Munich, Munich, Germany
| | - A Orekhov
- Department of Chemistry, Technical University of Munich, Munich, Germany
| | - H Ebert
- Department of Chemistry, Ludwig Maximilian University, Munich, Germany
| | - D Weiss
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - C H Back
- Department of Physics, Technical University of Munich, Munich, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
- Center for Quantum Engineering, Technical University of Munich, Munich, Germany
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4
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Xu Z, Zhu Y, Wang Y, Li X, Liu Q, Chen K, Wang J, Jiang Y, Chen L. Tailoring Dzyaloshinskii-Moriya Interaction and Spin-Hall Topological Hall Effect in Insulating Magnetic Oxides by Interface Engineering. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2403852. [PMID: 38984469 PMCID: PMC11425861 DOI: 10.1002/advs.202403852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 06/10/2024] [Indexed: 07/11/2024]
Abstract
Chiral spin textures, as exotic phases in magnetic materials, hold immense promise for revolutionizing logic, and memory applications. Recently, chiral spin textures have been observed in centrosymmetric magnetic insulators (FMI), due to an interfacial Dzyaloshinskii-Moriya interaction (iDMI). However, the source and origin of this iDMI remain enigmatic in magnetic insulator systems. Here, the source and origin of the iDMI in Pt/Y3Fe5O12 (YIG)/substrate structures are deeply delved by examining the spin-Hall topological Hall effect (SH-THE), an indication of chiral spin textures formed due to an iDMI. Through carefully modifying the interfacial chemical composition of Pt/YIG/substrate with a nonmagnetic Al3+ doping, the obvious dependence of SH-THE on the interfacial chemical composition for both the heavy metal (HM)/FMI and FMI/substrate interfaces is observed. The results reveal that both interfaces contribute to the strength of the iDMI, and the iDMI arises due to strong spin-orbit coupling and inversion symmetry breaking at both interfaces in HM/FMI/substrate. Importantly, it is shown that nonmagnetic substitution and interface engineering can significantly tune the SH-THE and iDMI in ferrimagnetic iron garnets. The approach offers a viable route to tailor the iDMI and associated chiral spin textures in low-damping insulating magnetic oxides, thus advancing the field of spintronics.
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Affiliation(s)
- Zedong Xu
- Institute of Quantum Materials and Devices, School of Electronics and Information Engineering, Tiangong University, Tianjin, 300387, China
| | - Yuanmin Zhu
- School of Materials Science and Engineering, Dongguan University of Technology, Dongguan, 523808, China
| | - Yuming Wang
- Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xiaowen Li
- Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Qi Liu
- Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Kai Chen
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230026, China
| | - Junling Wang
- Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Yong Jiang
- Institute of Quantum Materials and Devices, School of Electronics and Information Engineering, Tiangong University, Tianjin, 300387, China
| | - Lang Chen
- Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
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5
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Suresh S, Sadhu SPP, Mishra V, Paulus W, Ramachandra Rao MS. Tunable charge transport properties in non-stoichiometric SrIrO 3thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:425601. [PMID: 38981585 DOI: 10.1088/1361-648x/ad6111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 07/09/2024] [Indexed: 07/11/2024]
Abstract
Delving into the intricate interplay between spin-orbit coupling and Coulomb correlations in strongly correlated oxides, particularly perovskite compounds, has unveiled a rich landscape of exotic phenomena ranging from unconventional superconductivity to the emergence of topological phases. In this study, we have employed pulsed laser deposition technique to grow SrIrO3(SIO) thin films on SrTiO3substrates, systematically varying the oxygen content during the post-deposition annealing. X-ray photoelectron spectroscopy (XPS) provided insights into the stoichiometry and spin-orbit splitting energy of Iridium within the SIO film, while high-resolution x-ray studies meticulously examined the structural integrity of the thin films. Remarkably, our findings indicate a decrease in the metallicity of SIO thin films with reduced annealing O2partial pressure. Furthermore, we carried out magneto-transport studies on the SIO thin films, the results revealed intriguing insights into spin transport as a function of oxygen content. The tunability of the electronic band structure of SIO films with varying oxygen vacancy is correlated with the density functional theory calculations. Our findings elucidate the intricate mechanisms dictating spin transport properties in SIO thin films, offering invaluable guidance for the design and optimization of spintronic devices based on complex oxide materials. Notably, the ability to tune bandwidth by varying post-annealing oxygen partial pressure in iridate-based spintronic materials holds significant promise for advancing technological applications in the spintronics domain.
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Affiliation(s)
- Sreya Suresh
- Department of Physics, Nano Functional Materials Technology Centre, Quantum Centre of Excellence for Diamond and Emergent Materials, and Materials Science Research Centre, Indian Institute of Technology Madras, Chennai 600 036, India
| | - Sai Pavan Prashanth Sadhu
- Department of Physics, Indian Institute of Information Technology, Design and Manufacturing, Kancheepuram, Chennai 600 127, India
| | - Vikash Mishra
- Department of Physics, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka 576 104, India
| | - Werner Paulus
- ICGM, Univ Montpellier, CNRS, ENSCM, 34000, Montpellier, France
| | - M S Ramachandra Rao
- Department of Physics, Nano Functional Materials Technology Centre, Quantum Centre of Excellence for Diamond and Emergent Materials, and Materials Science Research Centre, Indian Institute of Technology Madras, Chennai 600 036, India
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6
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Johansson A. Theory of spin and orbital Edelstein effects. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:423002. [PMID: 38955339 DOI: 10.1088/1361-648x/ad5e2b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Accepted: 07/01/2024] [Indexed: 07/04/2024]
Abstract
In systems with broken spatial inversion symmetry, such as surfaces, interfaces, or bulk systems lacking an inversion center, the application of a charge current can generate finite spin and orbital densities associated with a nonequilibrium magnetization, which is known as spin and orbital Edelstein effect (SEE and OEE), respectively. Early reports on this current-induced magnetization focus on two-dimensional Rashba systems, in which an in-plane nonequilibrium spin density is generated perpendicular to the applied charge current. However, until today, a large variety of materials have been theoretically predicted and experimentally demonstrated to exhibit a sizeable Edelstein effect, which comprises contributions from the spin as well as the orbital degrees of freedom, and whose associated magnetization may be out of plane, nonorthogonal, and even parallel to the applied charge current, depending on the system's particular symmetries. In this review, we give an overview on the most commonly used theoretical approaches for the discussion and prediction of the SEE and OEE. Further, we introduce a selection of the most intensely discussed materials exhibiting a finite Edelstein effect, and give a brief summary of common experimental techniques.
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Affiliation(s)
- Annika Johansson
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
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7
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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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8
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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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9
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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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10
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Sala G, Wang H, Legrand W, Gambardella P. Orbital Hanle Magnetoresistance in a 3d Transition Metal. PHYSICAL REVIEW LETTERS 2023; 131:156703. [PMID: 37897743 DOI: 10.1103/physrevlett.131.156703] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/21/2023] [Indexed: 10/30/2023]
Abstract
The Hanle magnetoresistance is a telltale signature of spin precession in nonmagnetic conductors, in which strong spin-orbit coupling generates edge spin accumulation via the spin Hall effect. Here, we report the existence of a large Hanle magnetoresistance in single layers of Mn with weak spin-orbit coupling, which we attribute to the orbital Hall effect. The simultaneous observation of a sizable Hanle magnetoresistance and vanishing small spin Hall magnetoresistance in BiYIG/Mn bilayers corroborates the orbital origin of both effects. We estimate an orbital Hall angle of 0.016, an orbital relaxation time of 2 ps and diffusion length of the order of 2 nm in disordered Mn. Our findings indicate that current-induced orbital moments are responsible for magnetoresistance effects comparable to or even larger than those determined by spin moments, and provide a tool to investigate nonequilibrium orbital transport phenomena.
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Affiliation(s)
- Giacomo Sala
- Department of Materials, ETH Zurich, Hönggerbergring 64, 8093 Zurich, Switzerland
| | - Hanchen Wang
- Department of Materials, ETH Zurich, Hönggerbergring 64, 8093 Zurich, Switzerland
| | - William Legrand
- Department of Materials, ETH Zurich, Hönggerbergring 64, 8093 Zurich, Switzerland
| | - Pietro Gambardella
- Department of Materials, ETH Zurich, Hönggerbergring 64, 8093 Zurich, Switzerland
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11
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Zhao Q, Zhu Y, Zhang H, Jiang B, Wang Y, Xie T, Lou K, Xia C, Yang H, Bi C. Proximity-Induced Interfacial Room-Temperature Ferromagnetism in Semiconducting Fe 3GeTe 2. ACS APPLIED MATERIALS & INTERFACES 2023; 15:46520-46526. [PMID: 37738105 DOI: 10.1021/acsami.3c09932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
The discoveries of two-dimensional ferromagnetism and magnetic semiconductors highly enrich the magnetic material family for constructing spin-based electronic devices, but with an acknowledged challenge that the Curie temperature (Tc) is usually far below room temperature. Many efforts such as voltage control and magnetic ion doping are currently underway to enhance the functional temperature, in which the involvement of additional electrodes or extra magnetic ions limits their application in practical devices. Here we demonstrate that the magnetic proximity, a robust effect but with elusive mechanisms, can induce room-temperature ferromagnetism at the interface between sputtered Pt and semiconducting Fe3GeTe2, both of which do not show ferromagnetism at 300 K. The independent electrical and magnetization measurements, structure analysis, and control samples with Ta highlighting the role of Pt confirm that the ferromagnetism with the Tc of above 400 K arises from the Fe3GeTe2/Pt interfaces, rather than Fe aggregation or other artificial effects. Moreover, contrary to conventional ferromagnet/Pt structures, the spin current generated by the Pt layer is enhanced more than two times at the Fe3GeTe2/Pt interfaces, indicating the potential applications of the unique proximity effect in building highly efficient spintronic devices. These results may pave a new avenue to create room-temperature functional spin devices based on low-Tc materials and provide clear evidence of magnetic proximity effects by using nonferromagnetic materials.
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Affiliation(s)
- Qianwen Zhao
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingmei Zhu
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Hanying Zhang
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baiqing Jiang
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan Wang
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tunan Xie
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kaihua Lou
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - ChaoChao Xia
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
| | - Hongxin Yang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Chong Bi
- Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Microelectronics, University of Science and Technology of China, Hefei 230026, China
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12
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Zheng XY, Channa S, Riddiford LJ, Wisser JJ, Mahalingam K, Bowers CT, McConney ME, N'Diaye AT, Vailionis A, Cogulu E, Ren H, Galazka Z, Kent AD, Suzuki Y. Ultra-thin lithium aluminate spinel ferrite films with perpendicular magnetic anisotropy and low damping. Nat Commun 2023; 14:4918. [PMID: 37582804 PMCID: PMC10427713 DOI: 10.1038/s41467-023-40733-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 08/07/2023] [Indexed: 08/17/2023] Open
Abstract
Ultra-thin films of low damping ferromagnetic insulators with perpendicular magnetic anisotropy have been identified as critical to advancing spin-based electronics by significantly reducing the threshold for current-induced magnetization switching while enabling new types of hybrid structures or devices. Here, we have developed a new class of ultra-thin spinel structure Li0.5Al1.0Fe1.5O4 (LAFO) films on MgGa2O4 (MGO) substrates with: 1) perpendicular magnetic anisotropy; 2) low magnetic damping and 3) the absence of degraded or magnetic dead layers. These films have been integrated with epitaxial Pt spin source layers to demonstrate record low magnetization switching currents and high spin-orbit torque efficiencies. These LAFO films on MGO thus combine all of the desirable properties of ferromagnetic insulators with perpendicular magnetic anisotropy, opening new possibilities for spin based electronics.
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Affiliation(s)
- Xin Yu Zheng
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA.
| | - Sanyum Channa
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
- Department of Physics, Stanford University, Stanford, CA, USA
| | - Lauren J Riddiford
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
| | - Jacob J Wisser
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | | | - Cynthia T Bowers
- Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, OH, 05433, USA
| | - Michael E McConney
- Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, OH, 05433, USA
| | - Alpha T N'Diaye
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Arturas Vailionis
- Stanford Nano Shared Facilities, Stanford University, Stanford, CA, 94305, USA
- Department of Physics, Kaunas University of Technology, Studentu Street 50, LT-51368, Kaunas, Lithuania
| | - Egecan Cogulu
- Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA
| | - Haowen Ren
- Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA
| | - Zbigniew Galazka
- Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489, Berlin, Germany
| | - Andrew D Kent
- Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA
| | - Yuri Suzuki
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA
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13
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Nodo S, Yamane I, Suzuki M, Okabayashi J, Yokokura S, Shimada T, Nagahama T. Intrinsic Magnetic Proximity Effect at the Atomically Sharp Interface of Co xFe 3-xO 4/Pt Grown by Molecular Beam Epitaxy. ACS OMEGA 2023; 8:24875-24882. [PMID: 37483234 PMCID: PMC10357544 DOI: 10.1021/acsomega.3c00935] [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: 02/12/2023] [Accepted: 06/15/2023] [Indexed: 07/25/2023]
Abstract
CoxFe3-xO4(CFO)/Pt bilayers prepared by molecular beam epitaxy were investigated for the anomalous Hall effect and X-ray magnetic circular dichroism (XMCD). We found that the anomalous Hall effect originates from a magnetic proximity effect at the CFO/Pt interface. The XMCD signal in the Pt L-edge was obtained only for the sample deposited at 600 °C, indicating that the magnetic proximity effect is sensitive to the interface structure. Transmission electron microscopy images of the CFO/Pt interface and XMCD measurements of Co and Fe L-edges do not provide direct evidence for interfacial atomic diffusion or alloying. In summary, these results suggest that the magnetic proximity effect is robust for transport properties, such as the anomalous Hall effect, while the induced magnetic moment depends on slight differences in the interfacial structure, such as the presence or absence of interfacial oxygen ions.
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Affiliation(s)
- Shoto Nodo
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Ichiro Yamane
- Graduate
School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Motohiro Suzuki
- School
of Engineering, Kwansei Gakuin University, Sanda, Hyogo 669-1330, Japan
| | - Jun Okabayashi
- Research
Center for Spectrochemistry, The University
of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Seiya Yokokura
- Graduate
School of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Toshihiro Shimada
- Graduate
School of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Taro Nagahama
- Graduate
School of Engineering, Hokkaido University, Sapporo 060-8628, Japan
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14
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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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15
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Rosenberg E, Bauer J, Cho E, Kumar A, Pelliciari J, Occhialini CA, Ning S, Kaczmarek A, Rosenberg R, Freeland JW, Chen YC, Wang JP, LeBeau J, Comin R, de Groot FMF, Ross CA. Revealing Site Occupancy in a Complex Oxide: Terbium Iron Garnet. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023:e2300824. [PMID: 37060220 DOI: 10.1002/smll.202300824] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Indexed: 06/19/2023]
Abstract
Complex oxide films stabilized by epitaxial growth can exhibit large populations of point defects which have important effects on their properties. The site occupancy of pulsed laser-deposited epitaxial terbium iron garnet (TbIG) films with excess terbium (Tb) is analyzed, in which the terbium:iron (Tb:Fe)ratio is 0.86 compared to the stoichiometric value of 0.6. The magnetic properties of the TbIG are sensitive to site occupancy, exhibiting a higher compensation temperature (by 90 K) and a lower Curie temperature (by 40 K) than the bulk Tb3 Fe5 O12 garnet. Data derived from X-ray core-level spectroscopy, magnetometry, and molecular field coefficient modeling are consistent with occupancy of the dodecahedral sites by Tb3+ , the octahedral sites by Fe3+ , Tb3+ and vacancies, and the tetrahedral sites by Fe3+ and vacancies. Energy dispersive X-ray spectroscopy in a scanning transmission electron microscope provides direct evidence of TbFe antisites. A small fraction of Fe2+ is present, and oxygen vacancies are inferred to be present to maintain charge neutrality. Variation of the site occupancies provides a path to considerable manipulation of the magnetic properties of epitaxial iron garnet films and other complex oxides, which readily accommodate stoichiometries not found in their bulk counterparts.
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Affiliation(s)
- Ethan Rosenberg
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- 3M Corporate Research Materials Laboratory, 3M Center, St. Paul, MN, 55114, USA
| | - Jackson Bauer
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Eunsoo Cho
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Abinash Kumar
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Jonathan Pelliciari
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, United States
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Connor A Occhialini
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, United States
| | - Shuai Ning
- School of Materials Science and Engineering, Nankai University, Tianjin, 300350, P. R. China
| | - Allison Kaczmarek
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Richard Rosenberg
- Advanced Photon Source, X-Ray Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - John W Freeland
- Advanced Photon Source, X-Ray Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Yu-Chia Chen
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - Jian-Ping Wang
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota, 55455, USA
| | - James LeBeau
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Riccardo Comin
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, United States
| | - F M F de Groot
- Materials Chemistry and Catalysis, Utrecht University, Universiteitslaan 99, Utrecht, 3584 CG, Netherlands
| | - Caroline A Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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16
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An T, Cui B, Liu L, Zhang M, Liu F, Liu W, Xie J, Ren X, Chu R, Cheng B, Jiang C, Hu J. Enhanced Spin Current in Ni 81 Fe 19 /Cu-CuO x Bilayer with Top and Sideways Oxidization. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207988. [PMID: 36630709 DOI: 10.1002/adma.202207988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 01/06/2023] [Indexed: 06/17/2023]
Abstract
Generation and manipulation of spin current are the cores of spintronic devices, which are intensely pursued. Heavy metals with strong spin-orbit coupling are commonly used for the generation of spin current, but are incompatible with the mass production of devices, and the polarization of spin current is limited to be in-plane. Here, it is shown that the spin current with strong out-of-plane polarization component can be generated and transmitted in Ni81 Fe19 /Cu-CuOx bilayer with sideways and top oxidizations. The charge-to-spin current conversion efficiency can be enhanced through the spin currents consisting of both out-of-plane polarization (σz ) and in-plane polarization (σy ) induced by spin-vorticity coupling. Such a spin current is demonstrated to be closely related to the lateral oxidization gradient and can be controlled by changing the temperatures and times of annealing. The finding here provides a novel degree of freedom to produce and control the spin current in spintronic devices.
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Affiliation(s)
- Taiyu An
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan, 250100, China
| | - Bin Cui
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan, 250100, China
| | - Liang Liu
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan, 250100, China
| | - Mingfang Zhang
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan, 250100, China
| | - Fufu Liu
- Key Laboratory for Magnetism and Magnetic Materials, Ministry of Education, Lanzhou University, Lanzhou, 730000, China
- Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Weikang Liu
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan, 250100, China
| | - Jihao Xie
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan, 250100, China
| | - Xue Ren
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan, 250100, China
| | - Ruiyue Chu
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan, 250100, China
| | - Bin Cheng
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan, 250100, China
| | - Changjun Jiang
- Key Laboratory for Magnetism and Magnetic Materials, Ministry of Education, Lanzhou University, Lanzhou, 730000, China
- Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Jifan Hu
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan, 250100, China
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17
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Zhu L, Ralph DC. Strong variation of spin-orbit torques with relative spin relaxation rates in ferrimagnets. Nat Commun 2023; 14:1778. [PMID: 36997579 PMCID: PMC10063689 DOI: 10.1038/s41467-023-37506-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 03/20/2023] [Indexed: 04/03/2023] Open
Abstract
Spin-orbit torques (SOTs) have been widely understood as an interfacial transfer of spin that is independent of the bulk properties of the magnetic layer. Here, we report that SOTs acting on ferrimagnetic FexTb1-x layers decrease and vanish upon approaching the magnetic compensation point because the rate of spin transfer to the magnetization becomes much slower than the rate of spin relaxation into the crystal lattice due to spin-orbit scattering. These results indicate that the relative rates of competing spin relaxation processes within magnetic layers play a critical role in determining the strength of SOTs, which provides a unified understanding for the diverse and even seemingly puzzling SOT phenomena in ferromagnetic and compensated systems. Our work indicates that spin-orbit scattering within the magnet should be minimized for efficient SOT devices. We also find that the interfacial spin-mixing conductance of interfaces of ferrimagnetic alloys (such as FexTb1-x) is as large as that of 3d ferromagnets and insensitive to the degree of magnetic compensation.
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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.
| | - Daniel C Ralph
- Cornell University, Ithaca, NY, 14850, USA
- Kavli Institute at Cornell, Ithaca, NY, 14850, USA
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18
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Liang Y, Wu L, Dai M, Zhang Y, Zhang Q, Wang J, Zhang N, Xu W, Le Zhao, Chen H, Ma J, Wu J, Cao Y, Yi D, Ma J, Jiang W, Hu J, Nan C, Lin Y. Significant Unconventional Anomalous Hall Effect in Heavy Metal/Antiferromagnetic Insulator Heterostructures. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2206203. [PMID: 36703616 PMCID: PMC10015866 DOI: 10.1002/advs.202206203] [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: 10/25/2022] [Revised: 01/13/2023] [Indexed: 09/15/2024]
Abstract
The anomalous Hall effect (AHE) is a quantum coherent transport phenomenon that conventionally vanishes at elevated temperatures because of thermal dephasing. Therefore, it is puzzling that the AHE can survive in heavy metal (HM)/antiferromagnetic (AFM) insulator (AFMI) heterostructures at high temperatures yet disappears at low temperatures. In this paper, an unconventional high-temperature AHE in HM/AFMI is observed only around the Néel temperature of AFM, with large anomalous Hall resistivity up to 40 nΩ cm is reported. This mechanism is attributed to the emergence of a noncollinear AFM spin texture with a non-zero net topological charge. Atomistic spin dynamics simulation shows that such a unique spin texture can be stabilized by the subtle interplay among the collinear AFM exchange coupling, interfacial Dyzaloshinski-Moriya interaction, thermal fluctuation, and bias magnetic field.
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Affiliation(s)
- Yuhan Liang
- School of Materials Science and EngineeringTsinghua UniversityBeijing100084China
| | - Liang Wu
- Faculty of Materials Science and EngineeringKunming University of Science and TechnologyKunmingYunnan650093China
| | - Minyi Dai
- Department of Materials Science and EngineeringUniversity of Wisconsin‐MadisonMadisonWI53706USA
| | - Yujun Zhang
- Institute of High Energy PhysicsChinese Academy of SciencesBeijing100049China
| | - Qinghua Zhang
- Institute of PhysicsChinese Academy of SciencesBeijing100049China
| | - Jie Wang
- Institute of PhysicsChinese Academy of SciencesBeijing100049China
| | - Nian Zhang
- State Key Laboratory of Functional Materials for InformaticsShanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai200050China
- CAS Center for Excellence in Superconducting Electronics (CENSE)Chinese Academy of SciencesShanghai200050China
| | - Wei Xu
- Institute of High Energy PhysicsChinese Academy of SciencesBeijing100049China
| | - Le Zhao
- Department of PhysicsTsinghua UniversityBeijing10084China
| | - Hetian Chen
- School of Materials Science and EngineeringTsinghua UniversityBeijing100084China
| | - Ji Ma
- Faculty of Materials Science and EngineeringKunming University of Science and TechnologyKunmingYunnan650093China
| | - Jialu Wu
- School of Materials Science and EngineeringTsinghua UniversityBeijing100084China
| | - Yanwei Cao
- Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingboZhejiang315021China
- Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of SciencesBeijing100049China
| | - Di Yi
- School of Materials Science and EngineeringTsinghua UniversityBeijing100084China
| | - Jing Ma
- School of Materials Science and EngineeringTsinghua UniversityBeijing100084China
| | - Wanjun Jiang
- Department of PhysicsTsinghua UniversityBeijing10084China
| | - Jia‐Mian Hu
- Department of Materials Science and EngineeringUniversity of Wisconsin‐MadisonMadisonWI53706USA
| | - Ce‐Wen Nan
- School of Materials Science and EngineeringTsinghua UniversityBeijing100084China
| | - Yuan‐Hua Lin
- School of Materials Science and EngineeringTsinghua UniversityBeijing100084China
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19
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Aftergood J, Takei S. Conductivity Enhancement in a Diffusive Fermi Liquid due to Bose-Einstein Condensation of Magnons. PHYSICAL REVIEW LETTERS 2023; 130:086702. [PMID: 36898110 DOI: 10.1103/physrevlett.130.086702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 08/18/2022] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
We theoretically study the conductivity of a disordered 2D metal when it is coupled to ferromagnetic magnons with a quadratic spectrum and a gap Δ. In the diffusive limit, a combination of disorder and magnon-mediated electron interaction leads to a sharp metallic correction to the Drude conductivity as the magnons approach criticality, i.e., Δ→0. The correction is nonsingular and is distinctively weaker than, for example, the log-squared correction obtained when disordered electrons couple to diffusive spin fluctuations near a Hertz-Millis transition. The possibility of verifying this prediction in an S=1/2 easy-plane ferromagnetic insulator K_{2}CuF_{4} under an external magnetic field is proposed. Our results show that the onset of a magnon Bose-Einstein condensation in an insulator can be detected via electrical transport measurements on the proximate metal.
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Affiliation(s)
- Joshua Aftergood
- Department of Physics, Queens College of the City University of New York, Queens, New York 11367, USA
- The Graduate Center of the City University of New York, New York, New York 10016, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - So Takei
- Department of Physics, Queens College of the City University of New York, Queens, New York 11367, USA
- The Graduate Center of the City University of New York, New York, New York 10016, USA
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20
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Cheng Y, Tang J, Michel JJ, Chong SK, Yang F, Cheng R, Wang KL. Unidirectional Spin Hall Magnetoresistance in Antiferromagnetic Heterostructures. PHYSICAL REVIEW LETTERS 2023; 130:086703. [PMID: 36898091 DOI: 10.1103/physrevlett.130.086703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
Unidirectional spin Hall magnetoresistance (USMR) has been widely reported in the heavy metal/ferromagnet bilayer systems. We observe the USMR in Pt/α-Fe_{2}O_{3} bilayers where the α-Fe_{2}O_{3} is an antiferromagnetic (AFM) insulator. Systematic field and temperature dependent measurements confirm the magnonic origin of the USMR. The appearance of AFM-USMR is driven by the imbalance of creation and annihilation of AFM magnons by spin orbit torque due to the thermal random field. However, unlike its ferromagnetic counterpart, theoretical modeling reveals that the USMR in Pt/α-Fe_{2}O_{3} is determined by the antiferromagtic magnon number with a non-monotonic field dependence. Our findings extend the generality of the USMR which pave the ways for the highly sensitive detection of AFM spin state.
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Affiliation(s)
- Yang Cheng
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Junyu Tang
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - Justin J Michel
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Su Kong Chong
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Fengyuan Yang
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Ran Cheng
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
- Department of Electrical and Computer Engineering, University of California, Riverside, California 92521, USA
| | - Kang L Wang
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
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21
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Hung CM, Dang DTX, Chanda A, Detellem D, Alzahrani N, Kapuruge N, Pham YTH, Liu M, Zhou D, Gutierrez HR, Arena DA, Terrones M, Witanachchi S, Woods LM, Srikanth H, Phan MH. Enhanced Magnetism and Anomalous Hall Transport through Two-Dimensional Tungsten Disulfide Interfaces. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:771. [PMID: 36839139 PMCID: PMC9967397 DOI: 10.3390/nano13040771] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 05/14/2023]
Abstract
The magnetic proximity effect (MPE) has recently been explored to manipulate interfacial properties of two-dimensional (2D) transition metal dichalcogenide (TMD)/ferromagnet heterostructures for use in spintronics and valleytronics. However, a full understanding of the MPE and its temperature and magnetic field evolution in these systems is lacking. In this study, the MPE has been probed in Pt/WS2/BPIO (biphase iron oxide, Fe3O4 and α-Fe2O3) heterostructures through a comprehensive investigation of their magnetic and transport properties using magnetometry, four-probe resistivity, and anomalous Hall effect (AHE) measurements. Density functional theory (DFT) calculations are performed to complement the experimental findings. We found that the presence of monolayer WS2 flakes reduces the magnetization of BPIO and hence the total magnetization of Pt/WS2/BPIO at T > ~120 K-the Verwey transition temperature of Fe3O4 (TV). However, an enhanced magnetization is achieved at T < TV. In the latter case, a comparative analysis of the transport properties of Pt/WS2/BPIO and Pt/BPIO from AHE measurements reveals ferromagnetic coupling at the WS2/BPIO interface. Our study forms the foundation for understanding MPE-mediated interfacial properties and paves a new pathway for designing 2D TMD/magnet heterostructures for applications in spintronics, opto-spincaloritronics, and valleytronics.
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Affiliation(s)
- Chang-Ming Hung
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Diem Thi-Xuan Dang
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Amit Chanda
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Derick Detellem
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Noha Alzahrani
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Nalaka Kapuruge
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Yen T. H. Pham
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Mingzu Liu
- Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Da Zhou
- Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
| | | | - Darío A. Arena
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Mauricio Terrones
- Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sarath Witanachchi
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Lilia M. Woods
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Hariharan Srikanth
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Manh-Huong Phan
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
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22
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Wang XR, Wang C, Wang XS. A theory of unusual anisotropic magnetoresistance in bilayer heterostructures. Sci Rep 2023; 13:309. [PMID: 36609623 PMCID: PMC9823005 DOI: 10.1038/s41598-023-27530-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 01/03/2023] [Indexed: 01/09/2023] Open
Abstract
The observation of magnetoresistance (MR) varying with the rotation of magnetization in the plane perpendicular to the electric current is an important discovery in spintronics in recent years. The famous conventional anisotropic MR (AMR) says that the resistance of a polycrystalline magnetic material must depend on magnetization component along the current direction only, thus cannot account for this newly observed unusual AMR (UAMR). This UAMR leads to the notion of the spin-Hall MR (SMR) in the famous SMR theory. However, the SMR theory may only explain UAMR observed in heavy-metal/magnetic-insulator bilayers, not other types of bilayers. Here, we present a two-vector theory that can explain not only all existing experiments on the unusual angular dependence of longitudinal and transverse resistivity when the magnetization rotates in three mutually perpendicular planes, but also how three amplitudes of MR angular oscillation are related to each other. The theory is very general and its correctness depends only on the assumption that the magnetization and interfacial field are the only vectors affecting electron transport besides of other scalar variables such as the temperatures and impurities. Experiments that can test this theory against the SMR theory are also proposed.
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Affiliation(s)
- X. R. Wang
- grid.24515.370000 0004 1937 1450Physics Department, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong China ,grid.495521.eHKUST Shenzhen Research Institute, Shenzhen, 518057 China ,grid.24515.370000 0004 1937 1450William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong China
| | - C. Wang
- grid.33763.320000 0004 1761 2484Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, Tianjin, 300350 China
| | - X. S. Wang
- grid.67293.39School of Physics and Electronics, Hunan University, Changsha, 410082 China
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23
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Hui Y, Jiang H, Xie F, Lin W, Dong C, Dong K, He Q, Miao X. Maximizing spin Hall magnetoresistance in heavy metal/crystalline metallic ferromagnet multilayers with opposite spin Hall angles. NANOSCALE 2023; 15:820-827. [PMID: 36533700 DOI: 10.1039/d2nr02306g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Interconversion between charge and spin through spin-orbit coupling at a heavy metal (HM)/ferromagnet (FM) interface plays a key role in determining the amplitude of spin Hall magnetoresistance (SMR), which might maximally facilitate its applications in novel electronics. In this study, annealed NiFe films grown on MgO (100) substrates capped with Pt and Ta are reported to exhibit a maximum SMR. When the measuring temperature is reduced, the SMR rises and is significantly larger in crystalline NiFe than in amorphous NiFe. Another physical process for the negative SMR in Ta(dTa)/Pt(3 nm)/annealed NiFe samples is attributed to the interfacial spin-orbit coupling (ISOC) driven spin current (Js) generation and its reciprocal effects. Moreover, spin accumulation is enhanced at Pt(3 nm)/annealed NiFe interfaces after capping with a Ta layer, which functions as a spin sink in a certain thinner thickness range. With the cooperative interaction of choosing the proper Ta's thickness and annealing NiFe layers, the maximum SMR is obtained. Our results pave the way for rational interface engineering to enhance SMR for developing high-efficiency spintronic devices.
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Affiliation(s)
- Yajuan Hui
- School of Automation, China University of Geosciences, Wuhan, 430074, China.
- Hubei key Laboratory of Advanced Control and Intelligent Automation for Complex Systems, Wuhan, 430074, China
- Engineering Research Center of Intelligent Technology for Geo-Exploration, Ministry of Education, Wuhan 430074, China
| | - Hui Jiang
- School of Automation, China University of Geosciences, Wuhan, 430074, China.
- Hubei key Laboratory of Advanced Control and Intelligent Automation for Complex Systems, Wuhan, 430074, China
- Engineering Research Center of Intelligent Technology for Geo-Exploration, Ministry of Education, Wuhan 430074, China
| | - Fei Xie
- School of Automation, China University of Geosciences, Wuhan, 430074, China.
- Hubei key Laboratory of Advanced Control and Intelligent Automation for Complex Systems, Wuhan, 430074, China
- Engineering Research Center of Intelligent Technology for Geo-Exploration, Ministry of Education, Wuhan 430074, China
| | - Weinan Lin
- Department of Physics, Xiamen University, Xiamen 361005, China.
| | - Chao Dong
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Kaifeng Dong
- School of Automation, China University of Geosciences, Wuhan, 430074, China.
- Hubei key Laboratory of Advanced Control and Intelligent Automation for Complex Systems, Wuhan, 430074, China
- Engineering Research Center of Intelligent Technology for Geo-Exploration, Ministry of Education, Wuhan 430074, China
| | - Qiang He
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
- Wuhan National Lab for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xiangshui Miao
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
- Wuhan National Lab for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
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24
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Hao R, Zhang K, Chen W, Qu J, Kang S, Zhang X, Zhu D, Zhao W. Significant Role of Interfacial Spin-Orbit Coupling in the Spin-to-Charge Conversion in Pt/NiFe Heterostructure. ACS APPLIED MATERIALS & INTERFACES 2022; 14:57321-57327. [PMID: 36525266 DOI: 10.1021/acsami.2c13434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
For the spin-to-charge conversion (SCC) in heavy metal/ferromagnet (HM/FM) heterostructure, the contribution of interfacial spin-orbit coupling (SOC) remains controversial. Here, we investigate the SCC process of the Pt/NiFe heterostructure by the spin pumping in YIG/Pt/NiFe/IrMn multilayers. Due to the exchange bias of NiFe/IrMn structure, the NiFe magnetization can be switched between magnetically unsaturated and saturated states by opposite resonance fields of YIG layer. The spin-pumping signal is found to decrease significantly when the NiFe magnetization is changed from the saturated state to the unsaturated state. Theoretical analysis indicates that the interfacial spin absorption is enhanced for the above-mentioned NiFe magnetic state change, which results in the increased and decreased spin flow in the Pt layer and across the Pt/NiFe interface, respectively. These results demonstrate that in our case the interfacial SOC effect at the Pt/NiFe interface is dominant over the bulk inverse spin Hall effect in the Pt layer. Our work reveals a significant role of interfacial SOC in the SCC in HM/FM heterostructure, which can promote the development of high-efficiency spintronic devices through interfacial engineering.
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Affiliation(s)
- Runrun Hao
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
| | - Kun Zhang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
| | - Weibin Chen
- School of Physics, Shandong University, Jinan 250100, China
| | - Junda Qu
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
| | - Shishou Kang
- School of Physics, Shandong University, Jinan 250100, China
| | - Xueying Zhang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
- Truth Instruments Co. Ltd., Qingdao 266000, China
| | - Dapeng Zhu
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
| | - Weisheng Zhao
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266000, China
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25
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Three-dimensional skyrmionic cocoons in magnetic multilayers. Nat Commun 2022; 13:6843. [DOI: 10.1038/s41467-022-34370-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/21/2022] [Indexed: 11/13/2022] Open
Abstract
AbstractThree-dimensional spin textures emerge as promising quasi-particles for encoding information in future spintronic devices. The third dimension provides more malleability regarding their properties and more flexibility for potential applications. However, the stabilization and characterization of such quasi-particles in easily implementable systems remain a work in progress. Here we observe a three-dimensional magnetic texture that sits in the interior of magnetic thin films aperiodic multilayers and possesses a characteristic ellipsoidal shape. Interestingly, these objects that we call skyrmionic cocoons can coexist with more standard tubular skyrmions going through all the multilayer as evidenced by the existence of two very different contrasts in room temperature magnetic force microscopy. The presence of these novel skyrmionic textures as well as the understanding of their layer resolved chiral and topological properties have been investigated by micromagnetic simulations. Finally, we show that the skyrmionic cocoons can be electrically detected using magneto-transport measurements.
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26
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Makushko P, Kosub T, Pylypovskyi OV, Hedrich N, Li J, Pashkin A, Avdoshenko S, Hübner R, Ganss F, Wolf D, Lubk A, Liedke MO, Butterling M, Wagner A, Wagner K, Shields BJ, Lehmann P, Veremchuk I, Fassbender J, Maletinsky P, Makarov D. Flexomagnetism and vertically graded Néel temperature of antiferromagnetic Cr2O3 thin films. Nat Commun 2022; 13:6745. [DOI: 10.1038/s41467-022-34233-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 10/13/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractAntiferromagnetic insulators are a prospective materials platform for magnonics, spin superfluidity, THz spintronics, and non-volatile data storage. A magnetomechanical coupling in antiferromagnets offers vast advantages in the control and manipulation of the primary order parameter yet remains largely unexplored. Here, we discover a new member in the family of flexoeffects in thin films of Cr2O3. We demonstrate that a gradient of mechanical strain can impact the magnetic phase transition resulting in the distribution of the Néel temperature along the thickness of a 50-nm-thick film. The inhomogeneous reduction of the antiferromagnetic order parameter induces a flexomagnetic coefficient of about 15 μB nm−2. The antiferromagnetic ordering in the inhomogeneously strained films can persist up to 100 °C, rendering Cr2O3 relevant for industrial electronics applications. Strain gradient in Cr2O3 thin films enables fundamental research on magnetomechanics and thermodynamics of antiferromagnetic solitons, spin waves and artificial spin ice systems in magnetic materials with continuously graded parameters.
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27
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Xu J, He J, Zhou JS, Qu D, Huang SY, Chien CL. Observation of Vector Spin Seebeck Effect in a Noncollinear Antiferromagnet. PHYSICAL REVIEW LETTERS 2022; 129:117202. [PMID: 36154395 DOI: 10.1103/physrevlett.129.117202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 05/16/2022] [Accepted: 08/15/2022] [Indexed: 06/16/2023]
Abstract
Spintronic phenomena to date have been established in magnets with collinear moments, where the spin injection through the spin Seebeck effect (SSE) is always along the out-of-plane direction. Here, we report the observation of a vector SSE in a noncollinear antiferromagnet (AF) LuFeO_{3}, where temperature gradient along the out-of-plane and also the in-plane directions can both inject a pure spin current and generate a voltage in the heavy metal via the inverse spin Hall effect (ISHE). We show that the thermovoltages are due to the magnetization from canted spins in LuFeO_{3}. Furthermore, in contrast to the challenges of generating, manipulating, and detecting spin current in collinear AFs, the vector SSE in LuFeO_{3} is readily viable in zero magnetic field and can be controlled by a small magnetic field of about 150 Oe at room temperature. The noncollinear AFs expand new realms for exploring spin phenomena and provide a new route to low-field antiferromagnetic spin caloritronics and magnonics.
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Affiliation(s)
- Jinsong Xu
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Jiaming He
- Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712, USA
| | - J-S Zhou
- Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712, USA
| | - Danru Qu
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Ssu-Yen Huang
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - C L Chien
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
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28
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Cheng Y, Cogulu E, Resnick RD, Michel JJ, Statuto NN, Kent AD, Yang F. Third harmonic characterization of antiferromagnetic heterostructures. Nat Commun 2022; 13:3659. [PMID: 35760929 PMCID: PMC9237044 DOI: 10.1038/s41467-022-31451-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 06/17/2022] [Indexed: 11/19/2022] Open
Abstract
Electrical switching of antiferromagnets is an exciting recent development in spintronics, which promises active antiferromagnetic devices with high speed and low energy cost. In this emerging field, there is an active debate about the mechanisms of current-driven switching of antiferromagnets. For heavy-metal/ferromagnet systems, harmonic characterization is a powerful tool to quantify current-induced spin-orbit torques and spin Seebeck effect and elucidate current-induced switching. However, harmonic measurement of spin-orbit torques has never been verified in antiferromagnetic heterostructures. Here, we report harmonic measurements in Pt/α-Fe2O3 bilayers, which are explained by our modeling of higher-order harmonic voltages. As compared with ferromagnetic heterostructures where all current-induced effects appear in the second harmonic signals, the damping-like torque and thermally-induced magnetoelastic effect contributions in Pt/α-Fe2O3 emerge in the third harmonic voltage. Our results provide a new path to probe the current-induced magnetization dynamics in antiferromagnets, promoting the application of antiferromagnetic spintronic devices.
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Affiliation(s)
- Yang Cheng
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
| | - Egecan Cogulu
- Department of Physics, Center for Quantum Phenomena, New York University, New York, NY, 10003, USA
| | - Rachel D Resnick
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
| | - Justin J Michel
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
| | - Nahuel N Statuto
- Department of Physics, Center for Quantum Phenomena, New York University, New York, NY, 10003, USA
| | - Andrew D Kent
- Department of Physics, Center for Quantum Phenomena, New York University, New York, NY, 10003, USA
| | - Fengyuan Yang
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA.
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29
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Cogulu E, Zhang H, Statuto NN, Cheng Y, Yang F, Cheng R, Kent AD. Quantifying Spin-Orbit Torques in Antiferromagnet-Heavy-Metal Heterostructures. PHYSICAL REVIEW LETTERS 2022; 128:247204. [PMID: 35776458 DOI: 10.1103/physrevlett.128.247204] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 06/02/2022] [Indexed: 06/15/2023]
Abstract
The effect of spin currents on the magnetic order of insulating antiferromagnets (AFMs) is of fundamental interest and can enable new applications. Toward this goal, characterizing the spin-orbit torques (SOTs) associated with AFM-heavy-metal (HM) interfaces is important. Here we report the full angular dependence of the harmonic Hall voltages in a predominantly easy-plane AFM, epitaxial c-axis oriented α-Fe_{2}O_{3} films, with an interface to Pt. By modeling the harmonic Hall signals together with the α-Fe_{2}O_{3} magnetic parameters, we determine the amplitudes of fieldlike and dampinglike SOTs. Out-of-plane field scans are shown to be essential to determining the dampinglike component of the torques. In contrast to ferromagnetic-heavy-metal heterostructures, our results demonstrate that the fieldlike torques are significantly larger than the dampinglike torques, which we correlate with the presence of a large imaginary component of the interface spin-mixing conductance. Our work demonstrates a direct way of characterizing SOTs in AFM-HM heterostructures.
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Affiliation(s)
- Egecan Cogulu
- Center for Quantum Phenomena, Department of Physics, New York University, New York 10003, USA
| | - Hantao Zhang
- Department of Electrical and Computer Engineering, University of California, Riverside, California 92521, USA
| | - Nahuel N Statuto
- Center for Quantum Phenomena, Department of Physics, New York University, New York 10003, USA
| | - Yang Cheng
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Fengyuan Yang
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Ran Cheng
- Department of Electrical and Computer Engineering, University of California, Riverside, California 92521, USA
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - Andrew D Kent
- Center for Quantum Phenomena, Department of Physics, New York University, New York 10003, USA
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30
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Li Y, Zheng D, Liu C, Zhang C, Fang B, Chen A, Ma Y, Manchon A, Zhang X. Current-Induced Magnetization Switching Across a Nearly Room-Temperature Compensation Point in an Insulating Compensated Ferrimagnet. ACS NANO 2022; 16:8181-8189. [PMID: 35549072 DOI: 10.1021/acsnano.2c01788] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Insulating compensated ferrimagnets, especially hosting room-temperature compensation points, are considered promising candidates for developing ultra-high-density and ultrafast magnonic devices owing to combining the characteristics of both ferromagnets and antiferromagnets. These intriguing features become outstanding close to their compensation points. However, their spin-orbit torque (SOT)-induced magnetization switching, particularly in the vicinity of the compensation points, remains unclear. Herein, we systematically investigated the SOT in insulating compensated ferrimagnetic Gd3Fe5O12/Pt heterostructures with perpendicular magnetic anisotropy. A nearly room-temperature compensation point (Tcomp ∼ 297 K) was consistently identified by the magnetization curves, spin Hall-induced anomalous Hall effect, and spin Hall magnetoresistance measurements. Moreover, using 100 ns duration pulsed current, deterministic current-induced magnetization switching below and above Tcomp, even at 294 and 301 K, was achieved with opposite switching polarity. It is found that a large current is required to switch the magnetization in the vicinity of Tcomp, although the effective SOT field increases close to Tcomp. Our finding provides alternative opportunities for exploring ultrafast room-temperature magnon-based devices.
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Affiliation(s)
- Yan Li
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Dongxing Zheng
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Chen Liu
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Chenhui Zhang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Bin Fang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Aitian Chen
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Yinchang Ma
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | | | - Xixiang Zhang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
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31
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Xu Z, Liu Q, Ji Y, Li X, Li J, Wang J, Chen L. Strain-Tunable Interfacial Dzyaloshinskii-Moriya Interaction and Spin-Hall Topological Hall Effect in Pt/Tm 3Fe 5O 12 Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2022; 14:16791-16799. [PMID: 35362315 DOI: 10.1021/acsami.1c22942] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The interfacial Dzyaloshinskii-Moriya interaction (DMI) in heavy-metal/ferromagnet heterostructures enables to stabilize and manipulate novel topological spin textures, such as skyrmions, which arise as potential logic and memory devices for future information technology. Along these lines, we study in this work the topological spin textures in the films of magnetic insulators by detecting the spin-Hall topological Hall effect (SH-THE). The SH-THE presents obvious dependence of epitaxial strain in Pt/Tm3Fe5O12 (TmIG) bilayers deposited on a series of (111)-oriented garnet substrates, indicating that the topological spin textures can be tuned by epitaxial strain in this system. It is interesting to note that the room-temperature and low-field peak of SH-THE is also recorded within the Pt/TmIG bilayer configuration. We have also examined the interfacial DMI in the Pt/TmIG bilayers by an extended droplet model. The results indicate that the epitaxial strain can effectively change the interfacial DMI in this system, suggesting that the strain-induced modification of the interfacial DMI is the driving force for the SH-THE and topological spin textures in the Pt/TmIG bilayers. Our outcomes open new exciting avenues and opportunities in engineering chiral magnetism and examining the future skyrmion technology in magnetic insulators through the application of epitaxial strain.
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Affiliation(s)
- Zedong Xu
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- School of Electronics and Information Engineering, Tiangong University, Tianjin 300387, China
| | - Qi Liu
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Yanjiang Ji
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Xiaowen Li
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Junxue Li
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Junling Wang
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Lang Chen
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
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32
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Ren Z, Lao B, Zheng X, Liao L, Lu Z, Li S, Yang Y, Cao B, Wen L, Zhao K, Wang L, Bai X, Hao X, Liao Z, Wang Z, Li RW. Emergence of Insulating Ferrimagnetism and Perpendicular Magnetic Anisotropy in 3d-5d Perovskite Oxide Composite Films for Insulator Spintronics. ACS APPLIED MATERIALS & INTERFACES 2022; 14:15407-15414. [PMID: 35324157 DOI: 10.1021/acsami.2c01849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Magnetic insulators with strong perpendicular magnetic anisotropy (PMA) play a key role in exploring pure spin current phenomena and developing ultralow-dissipation spintronic devices, rendering them highly desirable to develop new material platforms. Here, we report the epitaxial growth of La2/3Sr1/3MnO3 (LSMO)-SrIrO3 (SIO) composite oxide films (LSMIO) with different crystalline orientations fabricated by a sequential two-target ablation process by pulsed laser deposition. The LSMIO films exhibit high crystalline quality with a homogeneous mixture of LSMO and SIO at an atomic level. Ferrimagnetic and insulating transport characteristics are observed, with the temperature-dependent electric resistivity well fitted by the Mott variable-range-hopping model. Moreover, the LSMIO films show strong PMA. By further constructing all-perovskite-oxide heterostructures of the ferrimagnetic insulator LSMIO and a strong spin-orbital-coupled SIO layer, pronounced spin Hall magnetoresistance (SMR) and spin Hall-like anomalous Hall effect (SH-AHE) were observed. These results illustrate the potential application of the ferrimagnetic insulator LSMIO in developing all-oxide ultralow-dissipation spintronic devices.
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Affiliation(s)
- Zeliang Ren
- Nano Science and Technology Institute, University of Science and Technology of China, Hefei 230026, Anhui, China
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Bin Lao
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Xuan Zheng
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- New Materials Institute, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Lei Liao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zengxing Lu
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Sheng Li
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Yongjie Yang
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Bingshan Cao
- Nano Science and Technology Institute, University of Science and Technology of China, Hefei 230026, Anhui, China
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Lijie Wen
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China
| | - Kenan Zhao
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Lifen Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xuedong Bai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xianfeng Hao
- Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China
| | - Zhaoliang Liao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Zhiming Wang
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, 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
| | - Run-Wei Li
- CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, 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
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33
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Catalano S, Gomez-Perez JM, Aguilar-Pujol MX, Chuvilin A, Gobbi M, Hueso LE, Casanova F. Spin Hall Magnetoresistance Effect from a Disordered Interface. ACS APPLIED MATERIALS & INTERFACES 2022; 14:8598-8604. [PMID: 35119253 DOI: 10.1021/acsami.1c23411] [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 spin Hall magnetoresistance (SMR) emerged as a reference tool to investigate the magnetic properties of materials with an all-electrical setup. Its sensitivity to the magnetization of thin films and surfaces may turn it into a valuable technique to characterize van der Waals magnetic materials, which support long-range magnetic order in atomically thin layers. However, realistic surfaces can be affected by defects and disorder, which may result in unexpected artifacts in the SMR, rather than the sole appearance of electrical noise. Here, we study the SMR response of heterostructures combining a platinum (Pt) thin film with the van der Waals antiferromagnet MnPSe3 and observe a robust SMR-like signal, which turns out to originate from the presence of strong interfacial disorder in the system. We use transmission electron microscopy (TEM) to characterize the interface between MnPSe3 and Pt, revealing the formation of a few nanometer-thick platinum-chalcogen amorphous layer. The analysis of the transport and TEM measurements suggests that the signal arises from a disordered magnetic system formed at the Pt/MnPSe3 interface, washing out the interaction between the spins of the Pt electrons and the MnPSe3 magnetic lattice. Our results show that the damaged interfaces can yield an important contribution to SMR, questioning a widespread assumption on the role of disorder in such measurements.
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Affiliation(s)
- Sara Catalano
- CIC nanoGUNE, Donostia-San Sebastián, Basque Country 20018, Spain
| | | | | | - Andrey Chuvilin
- CIC nanoGUNE, Donostia-San Sebastián, Basque Country 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Basque Country 48009, Spain
| | - Marco Gobbi
- CIC nanoGUNE, Donostia-San Sebastián, Basque Country 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Basque Country 48009, Spain
- Centro de Física de Materiales CFM-MPC (CSIC-UPV/EHU), Donostia-San Sebastian, Basque Country 20018, Spain
| | - Luis E Hueso
- CIC nanoGUNE, Donostia-San Sebastián, Basque Country 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Basque Country 48009, Spain
| | - Fèlix Casanova
- CIC nanoGUNE, Donostia-San Sebastián, Basque Country 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Basque Country 48009, Spain
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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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35
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Zhu X, Xu Y, Cao C, Shang T, Xie Y, Zhan Q. Recent developments on the magnetic and electrical transport properties of FeRh- and Rh-based heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:144004. [PMID: 35026751 DOI: 10.1088/1361-648x/ac4b28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 01/13/2022] [Indexed: 06/14/2023]
Abstract
It is fascinating how the binary alloy FeRh has been the subject of a vast number of studies almost solely for a single-phase transition. This is, however, reasonable, considering how various degrees of freedom are intertwined around this phase transition. Furthermore, the tunability of this phase transition-the large response to tuning parameters, such as electric field and strain-endows FeRh huge potential in applications. Compared to the bulk counterpart, FeRh in the thin-film form is superior in many aspects: materials in thin-film form are often more technologically relevant in the first place; in addition, the substrates add extra dimensions to the tunability, especially when the substrate itself is multiferroic. Here we review recent developments on the magnetic and transport properties of heterostructures based on FeRh and its end-member Rh, with the latter providing a new route to exploiting spin-orbit interactions in functional spintronic heterostructures other than the more often employed 5dmetals. The methods utilized in the investigation of the physical properties in these systems, and the design principles employed in the engineering thereof may conceivably be extended to similar phase transitions to other magnetic materials.
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Affiliation(s)
- Xiaoyan Zhu
- Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai 200241, People's Republic of China
| | - Yang Xu
- Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai 200241, People's Republic of China
| | - Cuimei Cao
- Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai 200241, People's Republic of China
| | - Tian Shang
- Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai 200241, People's Republic of China
| | - Yali Xie
- Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People's Republic of China
| | - Qingfeng Zhan
- Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai 200241, People's Republic of China
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36
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Liu G, Wang XG, Luan ZZ, Zhou LF, Xia SY, Yang B, Tian YZ, Guo GH, Du J, Wu D. Magnonic Unidirectional Spin Hall Magnetoresistance in a Heavy-Metal-Ferromagnetic-Insulator Bilayer. PHYSICAL REVIEW LETTERS 2021; 127:207206. [PMID: 34860044 DOI: 10.1103/physrevlett.127.207206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
We report the observation of the unidirectional spin Hall magnetoresistance (USMR), which depends on the current or magnetization direction, in heavy-metal-ferromagnetic-insulator bilayer, Pt-Y_{3}Fe_{5}O_{12} (YIG). This USMR is apparently not caused by the mechanisms established in metallic bilayer, in which the ferromagnetic layer is required to be electrically conductive. From the magnetic field, current, temperature, and YIG thickness dependent measurements, the USMR is attributed to the asymmetric magnon creation and annihilation induced by the spin-orbit torque. This asymmetry and the resultant USMR are further revealed by the micromagnetic simulations combined with the spin-orbit torque and the spin drift-diffusion model. Our finding exhibits a nonlinear manipulation of magnons with the charge current.
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Affiliation(s)
- G Liu
- National Laboratory of Solid State Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - Xi-Guang Wang
- School of Physics and Electronics, Central South University, Changsha 410083, People's Republic of China
| | - Z Z Luan
- National Laboratory of Solid State Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - L F Zhou
- National Laboratory of Solid State Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - S Y Xia
- National Laboratory of Solid State Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - B Yang
- National Laboratory of Solid State Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - Y Z Tian
- National Laboratory of Solid State Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - Guang-Hua Guo
- School of Physics and Electronics, Central South University, Changsha 410083, People's Republic of China
| | - J Du
- National Laboratory of Solid State Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - D Wu
- National Laboratory of Solid State Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China
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37
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Ogrodnik P, Grochot K, Karwacki Ł, Kanak J, Prokop M, Chȩciński J, Skowroński W, Ziȩtek S, Stobiecki T. Study of Spin-Orbit Interactions and Interlayer Ferromagnetic Coupling in Co/Pt/Co Trilayers in a Wide Range of Heavy-Metal Thickness. ACS APPLIED MATERIALS & INTERFACES 2021; 13:47019-47032. [PMID: 34558910 PMCID: PMC8519406 DOI: 10.1021/acsami.1c11675] [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: 06/22/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
The spin-orbit torque, a torque induced by a charge current flowing through the heavy-metal-conducting layer with strong spin-orbit interactions, provides an efficient way to control the magnetization direction in heavy-metal/ferromagnet nanostructures, required for applications in the emergent magnetic technologies like random access memories, high-frequency nano-oscillators, or bioinspired neuromorphic computations. We study the interface properties, magnetization dynamics, magnetostatic features, and spin-orbit interactions within the multilayer system Ti(2)/Co(1)/Pt(0-4)/Co(1)/MgO(2)/Ti(2) (thicknesses in nanometers) patterned by optical lithography on micrometer-sized bars. In the investigated devices, Pt is used as a source of the spin current and as a nonmagnetic spacer with variable thickness, which enables the magnitude of the interlayer ferromagnetic exchange coupling to be effectively tuned. We also find the Pt thickness-dependent changes in magnetic anisotropies, magnetoresistances, effective Hall angles, and, eventually, spin-orbit torque fields at interfaces. The experimental findings are supported by the relevant interface structure-related simulations, micromagnetic, macrospin, as well as the spin drift-diffusion models. Finally, the contribution of the spin-orbital Edelstein-Rashba interfacial fields is also briefly discussed in the analysis.
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Affiliation(s)
- Piotr Ogrodnik
- Institute of Electronics, AGH University
of Science and Technology, 30-059 Kraków,
Poland
- Faculty of Physics, Warsaw University of
Technology, 00-662 Warsaw, Poland
| | - Krzysztof Grochot
- Institute of Electronics, AGH University
of Science and Technology, 30-059 Kraków,
Poland
- Faculty of Physics and Applied Computer Science,
AGH University of Science and Technology, 30-059
Kraków, Poland
| | - Łukasz Karwacki
- Institute for Theoretical Physics,
Utrecht University, Princetonplein 5, 3584 CC Utrecht,
The Netherlands
- Institute of Molecular Physics, Polish Academy
of Sciences, ul. M. Smoluchowskiego 17, 60-179 Poznań,
Poland
| | - Jarosław Kanak
- Institute of Electronics, AGH University
of Science and Technology, 30-059 Kraków,
Poland
| | - Michał Prokop
- Catalan Institute of Nanoscience and Nanotechnology
(ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona,
Spain
| | - Jakub Chȩciński
- Institute of Electronics, AGH University
of Science and Technology, 30-059 Kraków,
Poland
| | - Witold Skowroński
- Institute of Electronics, AGH University
of Science and Technology, 30-059 Kraków,
Poland
| | - Sławomir Ziȩtek
- Institute of Electronics, AGH University
of Science and Technology, 30-059 Kraków,
Poland
| | - Tomasz Stobiecki
- Institute of Electronics, AGH University
of Science and Technology, 30-059 Kraków,
Poland
- Faculty of Physics and Applied Computer Science,
AGH University of Science and Technology, 30-059
Kraków, Poland
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38
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Holanda J, Santos OA, Mendes JBS, Rezende SM. Spin-to-charge conversion and interface-induced spin Hall magnetoresistance in yttrium iron garnet/metallic bilayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:435803. [PMID: 34293724 DOI: 10.1088/1361-648x/ac16f7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
We report the investigation of spin-to-charge current interconversion process in hybrid structures of yttrium iron garnet (YIG)/metallic bilayers by means of two different experimental techniques: spin pumping effect (SPE) and spin Hall magnetoresistance (SMR). We demonstrate the evidence of a correlation between spin-to-charge conversion and SMR in bilayers of YIG/Pd, YIG/Pt, and YIG/IrMn. The correlation was verified directly in the spin Hall angles and the amplitudes of the voltage signals measured by the SPE and SMR techniques. The detection of SMR was carried out using the modulated magnetoresistance technique and lock-in amplifier detection. For these measurements, we present a simple model for the interpretation of the results. The results allow us to conclude that indeed the interface in the YIG/metallic bilayers has a dominant role in the spin-to-charge current conversion and SMR.
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Affiliation(s)
- J Holanda
- Departamento de Física, Universidade Federal do Espírito Santo, 29075-910, Vitória, ES, Brazil
| | - O Alves Santos
- Physics of Nanodevices, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, AG 9747, The Netherlands
| | - J B S Mendes
- Departamento de Física, Universidade Federal de Viçosa, 36570-900 Viçosa, MG, Brazil
| | - S M Rezende
- Departamento de Física, Universidade Federal de Pernambuco, 50670-901, Recife, PE, Brazil
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39
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Structure and transport properties of the novel (Dy,Er,Gd,Ho,Y)3Fe5O12 and (Dy,Gd,Ho,Sm,Y)3Fe5O12 high entropy garnets. Ann Ital Chir 2021. [DOI: 10.1016/j.jeurceramsoc.2020.12.052] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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40
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Hwee Wong GD, Xu Z, Gan W, Ang CCI, Law WC, Tang J, Zhang W, Wong PKJ, Yu X, Xu F, Wee ATS, Seet CS, Lew WS. Strain-Mediated Spin-Orbit Torque Enhancement in Pt/Co on Flexible Substrate. ACS NANO 2021; 15:8319-8327. [PMID: 33970603 DOI: 10.1021/acsnano.0c09404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Current-induced magnetization switching by spin-orbit torque generated in heavy metals offers an enticing realm for energy-efficient memory and logic devices. The spin Hall efficiency is a key parameter in describing the generation of spin current. Recent findings have reported enhancement of spin Hall efficiency by mechanical strain, but its origin remains elusive. Here, we demonstrate a 45% increase in spin Hall efficiency in the platinum/cobalt (Pt/Co) bilayer, of which 78% of the enhancement was preserved even after the strain was removed. Spin transparency and X-ray magnetic circular dichroism revealed that the enhancement was attributed to a bulk effect in the Pt layer. This was further confirmed by the linear relationship between the spin Hall efficiency and resistivity, which indicates an increase in skew-scattering. These findings shed light on the origin of enhancement and are promising in shaping future utilization of mechanical strain for energy-efficient devices.
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Affiliation(s)
- Grayson Dao Hwee Wong
- School of Physical & Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
- GLOBALFOUNDRIES Singapore Pte. Ltd., 60 Woodlands Industrial Park D Street 2, Singapore 738406
| | - Zhan Xu
- School of Physical & Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Weiliang Gan
- School of Physical & Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Calvin Ching Ian Ang
- School of Physical & Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Wai Cheung Law
- School of Physical & Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
- GLOBALFOUNDRIES Singapore Pte. Ltd., 60 Woodlands Industrial Park D Street 2, Singapore 738406
| | - Jiaxuan Tang
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Wen Zhang
- School of Microelectronics, Northwestern Polytechnical University, Xi'an 710072, China
| | - Ping Kwan Johnny Wong
- School of Microelectronics, Northwestern Polytechnical University, Xi'an 710072, China
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603
| | - Feng Xu
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Andrew T S Wee
- Department of Physics and Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546
| | - Chim Seng Seet
- GLOBALFOUNDRIES Singapore Pte. Ltd., 60 Woodlands Industrial Park D Street 2, Singapore 738406
| | - Wen Siang Lew
- School of Physical & Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
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41
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Panda SN, Majumder S, Bhattacharyya A, Dutta S, Choudhury S, Barman A. Structural Phase-Dependent Giant Interfacial Spin Transparency in W/CoFeB Thin-Film Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2021; 13:20875-20884. [PMID: 33886256 DOI: 10.1021/acsami.1c03776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Pure spin current has transformed the research field of conventional spintronics due to its various advantages, including energy efficiency. An efficient mechanism for generation of pure spin current is spin pumping, and high effective spin-mixing conductance (Geff) and interfacial spin transparency (T) are essential for its higher efficiency. By employing the time-resolved magneto-optical Kerr effect technique, we report here a giant value of T in substrate/W (t)/Co20Fe60B20 (d)/SiO2 (2 nm) thin-film heterostructures in the beta-tungsten (β-W) phase. We extract the spin diffusion length of W and spin-mixing conductance of the W/CoFeB interface from the variation of damping as a function of W and CoFeB thickness. This leads to a value of T = 0.81 ± 0.03 for the β-W/CoFeB interface. A stark variation of Geff and T with the thickness of the W layer is obtained in accordance with the structural phase transition and resistivity variation of W with its thickness. Effects such as spin memory loss and two-magnon scattering are found to have minor contributions to damping modulation in comparison to the spin pumping effect which is reconfirmed from the unchanged damping constant with the variation of Cu spacer layer thickness inserted between W and CoFeB. The giant interfacial spin transparency and its strong dependence on crystal structures of W will be important for future spin-orbitronic devices based on pure spin current.
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Affiliation(s)
- Surya Narayan Panda
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector-III, Salt Lake, Kolkata 700 106, India
| | - Sudip Majumder
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector-III, Salt Lake, Kolkata 700 106, India
| | - Arpan Bhattacharyya
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector-III, Salt Lake, Kolkata 700 106, India
| | - Soma Dutta
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector-III, Salt Lake, Kolkata 700 106, India
| | - Samiran Choudhury
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector-III, Salt Lake, Kolkata 700 106, India
| | - Anjan Barman
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector-III, Salt Lake, Kolkata 700 106, India
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42
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Alotibi S, Hickey BJ, Teobaldi G, Ali M, Barker J, Poli E, O'Regan DD, Ramasse Q, Burnell G, Patchett J, Ciccarelli C, Alyami M, Moorsom T, Cespedes O. Enhanced Spin-Orbit Coupling in Heavy Metals via Molecular Coupling. ACS APPLIED MATERIALS & INTERFACES 2021; 13:5228-5234. [PMID: 33470108 DOI: 10.1021/acsami.0c19403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
5d metals are used in electronics because of their high spin-orbit coupling (SOC) leading to efficient spin-electric conversion. When C60 is grown on a metal, the electronic structure is altered due to hybridization and charge transfer. In this work, we measure the spin Hall magnetoresistance for Pt/C60 and Ta/C60, finding that they are up to a factor of 6 higher than those for pristine metals, indicating a 20-60% increase in the spin Hall angle. At low fields of 1-30 mT, the presence of C60 increased the anisotropic magnetoresistance by up to 700%. Our measurements are supported by noncollinear density functional theory calculations, which predict a significant SOC enhancement by C60 that penetrates through the Pt layer, concomitant with trends in the magnetic moment of transport electrons acquired via SOC and symmetry breaking. The charge transfer and hybridization between the metal and C60 can be controlled by gating, so our results indicate the possibility of dynamically modifying the SOC of thin metals using molecular layers. This could be exploited in spin-transfer torque memories and pure spin current circuits.
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Affiliation(s)
- Satam Alotibi
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Bryan J Hickey
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Gilberto Teobaldi
- Scientific Computing Department, Science and Technology Facilities Council, Didcot OX11 0QX, U.K
- Beijing Computational Science Research Center, Beijing 100193, China
- Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool, Liverpool L69 3BX, U.K
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K
| | - Mannan Ali
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Joseph Barker
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Emiliano Poli
- Scientific Computing Department, Science and Technology Facilities Council, Didcot OX11 0QX, U.K
| | - David D O'Regan
- School of Physics, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and the SFI Advanced Materials and Bio-Engineering Research Centre (AMBER), Dublin 2, Ireland
| | - Quentin Ramasse
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
- SuperSTEM, SciTech Daresbury Science and Innovation Campus, Keckwick Lane, Daresbury WA4 4AD, U.K
| | - Gavin Burnell
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - James Patchett
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Chiara Ciccarelli
- SuperSTEM, SciTech Daresbury Science and Innovation Campus, Keckwick Lane, Daresbury WA4 4AD, U.K
| | - Mohammed Alyami
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Timothy Moorsom
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Oscar Cespedes
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
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43
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Cosset-Chéneau M, Vila L, Zahnd G, Gusakova D, Pham VT, Grèzes C, Waintal X, Marty A, Jaffrès H, Attané JP. Measurement of the Spin Absorption Anisotropy in Lateral Spin Valves. PHYSICAL REVIEW LETTERS 2021; 126:027201. [PMID: 33512209 DOI: 10.1103/physrevlett.126.027201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 11/20/2020] [Indexed: 06/12/2023]
Abstract
The spin absorption process in a ferromagnetic material depends on the spin orientation relative to the magnetization. Using a ferromagnet to absorb the pure spin current created within a lateral spin valve, we evidence and quantify a sizable orientation dependence of the spin absorption in Co, CoFe, and NiFe. These experiments allow us to determine the spin-mixing conductance, an elusive but fundamental parameter of the spin-dependent transport. We show that the obtained values cannot be understood within a model considering only the Larmor, transverse decoherence, and spin diffusion lengths, and rather suggest that the spin-mixing conductance is actually limited by the Sharvin conductance.
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Affiliation(s)
- M Cosset-Chéneau
- Université Grenoble Alpes, CEA, CNRS, INP-G, Spintec, F-38054 Grenoble, France
| | - L Vila
- Université Grenoble Alpes, CEA, CNRS, INP-G, Spintec, F-38054 Grenoble, France
| | - G Zahnd
- Université Grenoble Alpes, CEA, CNRS, INP-G, Spintec, F-38054 Grenoble, France
| | - D Gusakova
- Université Grenoble Alpes, CEA, CNRS, INP-G, Spintec, F-38054 Grenoble, France
| | - V T Pham
- Université Grenoble Alpes, CEA, CNRS, INP-G, Spintec, F-38054 Grenoble, France
| | - C Grèzes
- Université Grenoble Alpes, CEA, CNRS, INP-G, Spintec, F-38054 Grenoble, France
| | - X Waintal
- Université Grenoble Alpes, CEA, Pheliqs, F-38054 Grenoble, France
| | - A Marty
- Université Grenoble Alpes, CEA, CNRS, INP-G, Spintec, F-38054 Grenoble, France
| | - H Jaffrès
- Unité Mixte de Physique CNRS/Thales, University Paris-Sud and Université Paris-Saclay, 91767 Palaiseau, France
| | - J-P Attané
- Université Grenoble Alpes, CEA, CNRS, INP-G, Spintec, F-38054 Grenoble, France
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44
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Kawada T, Kawaguchi M, Funato T, Kohno H, Hayashi M. Acoustic spin Hall effect in strong spin-orbit metals. SCIENCE ADVANCES 2021; 7:7/2/eabd9697. [PMID: 33523974 PMCID: PMC7787480 DOI: 10.1126/sciadv.abd9697] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 11/13/2020] [Indexed: 06/12/2023]
Abstract
We report on the observation of the acoustic spin Hall effect that facilitates lattice motion-induced spin current via spin-orbit interaction (SOI). Under excitation of surface acoustic wave (SAW), we find that a spin current flows orthogonal to the SAW propagation in nonmagnetic metals (NMs). The acoustic spin Hall effect manifests itself in a field-dependent acoustic voltage in NM/ferromagnetic metal bilayers. The acoustic voltage takes a maximum when the NM layer thickness is close to its spin diffusion length, vanishes for NM layers with weak SOI, and increases linearly with the SAW frequency. To account for these results, we find that the spin current must scale with the SOI and the time derivative of the lattice displacement. These results, which imply the strong coupling of electron spins with rotating lattices via the SOI, show the potential of lattice dynamics to supply spin current in strong spin-orbit metals.
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Affiliation(s)
- Takuya Kawada
- Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan
| | - Masashi Kawaguchi
- Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan.
| | - Takumi Funato
- Department of Physics, Nagoya University, Nagoya 464-8602, Japan
| | - Hiroshi Kohno
- Department of Physics, Nagoya University, Nagoya 464-8602, Japan
| | - Masamitsu Hayashi
- Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan.
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45
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Koo HC, Kim SB, Kim H, Park TE, Choi JW, Kim KW, Go G, Oh JH, Lee DK, Park ES, Hong IS, Lee KJ. Rashba Effect in Functional Spintronic Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2002117. [PMID: 32930418 DOI: 10.1002/adma.202002117] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/28/2020] [Indexed: 06/11/2023]
Abstract
Exploiting spin transport increases the functionality of electronic devices and enables such devices to overcome physical limitations related to speed and power. Utilizing the Rashba effect at the interface of heterostructures provides promising opportunities toward the development of high-performance devices because it enables electrical control of the spin information. Herein, the focus is mainly on progress related to the two most compelling devices that exploit the Rashba effect: spin transistors and spin-orbit torque devices. For spin field-effect transistors, the gate-voltage manipulation of the Rashba effect and subsequent control of the spin precession are discussed, including for all-electric spin field-effect transistors. For spin-orbit torque devices, recent theories and experiments on interface-generated spin current are discussed. The future directions of manipulating the Rashba effect to realize fully integrated spin logic and memory devices are also discussed.
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Affiliation(s)
- Hyun Cheol Koo
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, South Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, South Korea
| | - Seong Been Kim
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, South Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, South Korea
| | - Hansung Kim
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, South Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, South Korea
| | - Tae-Eon Park
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, South Korea
| | - Jun Woo Choi
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, South Korea
| | - Kyoung-Whan Kim
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, South Korea
| | - Gyungchoon Go
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, South Korea
| | - Jung Hyun Oh
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, South Korea
| | - Dong-Kyu Lee
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, South Korea
| | - Eun-Sang Park
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, South Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, South Korea
| | - Ik-Sun Hong
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, South Korea
| | - Kyung-Jin Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, South Korea
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, South Korea
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46
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Kim KW, Lee KJ. Generalized Spin Drift-Diffusion Formalism in the Presence of Spin-Orbit Interaction of Ferromagnets. PHYSICAL REVIEW LETTERS 2020; 125:207205. [PMID: 33258628 DOI: 10.1103/physrevlett.125.207205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 08/20/2020] [Accepted: 10/09/2020] [Indexed: 06/12/2023]
Abstract
We generalize the spin drift-diffusion formalism by considering spin-orbit interaction of a ferromagnet, which generates transverse spin currents in the ferromagnet. We consider quantum-mechanical transport of transverse spins in a spin-orbit coupled ferromagnet and develop a generalized drift-diffusion equation and boundary condition. By combining them, we identify previously unrecognized spin transport phenomena in heterostructures including ferromagnets. As representative examples, we show self-generated spin torque and self-generated charge pumping in ferromagnet-normal metal bilayers. The former is a torque exerting on a ferromagnet, originating from a transverse spin current leaving from the ferromagnet itself, whereas the latter is the Onsager reciprocity of the former. Our work not only provides a concise formalism for the effects of nondephased transverse spins in ferromagnets but also enables to design spintronic devices without an external spin source.
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Affiliation(s)
- Kyoung-Whan Kim
- Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Kyung-Jin Lee
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
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47
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Ding S, Ross A, Go D, Baldrati L, Ren Z, Freimuth F, Becker S, Kammerbauer F, Yang J, Jakob G, Mokrousov Y, Kläui M. Harnessing Orbital-to-Spin Conversion of Interfacial Orbital Currents for Efficient Spin-Orbit Torques. PHYSICAL REVIEW LETTERS 2020; 125:177201. [PMID: 33156648 DOI: 10.1103/physrevlett.125.177201] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/05/2020] [Accepted: 09/03/2020] [Indexed: 06/11/2023]
Abstract
Current-induced spin-orbit torques (SOTs) allow for the efficient electrical manipulation of magnetism in spintronic devices. Engineering the SOT efficiency is a key goal that is pursued by maximizing the active interfacial spin accumulation or modulating the nonequilibrium spin density that builds up through the spin Hall and inverse spin galvanic effects. Regardless of the origin, the fundamental requirement for the generation of the current-induced torques is a net spin accumulation. We report on the large enhancement of the SOT efficiency in thulium iron garnet (TmIG)/Pt by capping with a CuO_{x} layer. Considering the weak spin-orbit coupling (SOC) of CuO_{x}, these surprising findings likely result from an orbital current generated at the interface between CuO_{x} and Pt, which is injected into the Pt layer and converted into a spin current by strong SOC. The converted spin current decays across the Pt layer and exerts a "nonlocal" torque on TmIG. This additional torque leads to a maximum colossal enhancement of the SOT efficiency of a factor 16 for 1.5 nm of Pt at room temperature, thus opening a path to increase torques while at the same time offering insights into the underlying physics of orbital transport, which has so far been elusive.
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Affiliation(s)
- Shilei Ding
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, 55128 Mainz, Germany
| | - Andrew Ross
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, 55128 Mainz, Germany
| | - Dongwook Go
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
| | - Lorenzo Baldrati
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Zengyao Ren
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, 55128 Mainz, Germany
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Frank Freimuth
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
| | - Sven Becker
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Fabian Kammerbauer
- 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, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
- Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing 100871, 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
| | - Yuriy Mokrousov
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, 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
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48
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Gomez-Perez JM, Zhang XP, Calavalle F, Ilyn M, González-Orellana C, Gobbi M, Rogero C, Chuvilin A, Golovach VN, Hueso LE, Bergeret FS, Casanova F. Strong Interfacial Exchange Field in a Heavy Metal/Ferromagnetic Insulator System Determined by Spin Hall Magnetoresistance. NANO LETTERS 2020; 20:6815-6823. [PMID: 32786952 DOI: 10.1021/acs.nanolett.0c02834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Spin-dependent transport at heavy metal/magnetic insulator interfaces is at the origin of many phenomena at the forefront of spintronics research. A proper quantification of the different interfacial spin conductances is crucial for many applications. Here, we report the first measurement of the spin Hall magnetoresistance (SMR) of Pt on a purely ferromagnetic insulator (EuS). We perform SMR measurements in a wide range of temperatures and fit the results by using a microscopic model. From this fitting procedure, we obtain the temperature dependence of the spin conductances (Gs, Gr, and Gi), disentangling the contribution of field-like torque (Gi), damping-like torque (Gr), and spin-flip scattering (Gs). An interfacial exchange field of the order of 1 meV acting upon the conduction electrons of Pt can be estimated from Gi, which is at least three times larger than Gr below the Curie temperature. Our work provides an easy method to quantify this interfacial spin-splitting field, which plays a key role in emerging fields such as superconducting spintronics and caloritronics as well as topological quantum computation.
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Affiliation(s)
| | - Xian-Peng Zhang
- Donostia International Physics Center, 20018 Donostia-San Sebastian, Basque Country, Spain
- Centro de Fı́sica de Materiales CFM-MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastian, Basque Country, Spain
| | | | - Maxim Ilyn
- Centro de Fı́sica de Materiales CFM-MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastian, Basque Country, Spain
| | - Carmen González-Orellana
- Centro de Fı́sica de Materiales CFM-MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastian, Basque Country, Spain
| | - Marco Gobbi
- CIC nanoGUNE BRTA, 20018 Donostia-San Sebastian, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
- Centro de Fı́sica de Materiales CFM-MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastian, Basque Country, Spain
| | - Celia Rogero
- Donostia International Physics Center, 20018 Donostia-San Sebastian, Basque Country, Spain
- Centro de Fı́sica de Materiales CFM-MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastian, Basque Country, Spain
| | - Andrey Chuvilin
- CIC nanoGUNE BRTA, 20018 Donostia-San Sebastian, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
| | - Vitaly N Golovach
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
- Donostia International Physics Center, 20018 Donostia-San Sebastian, Basque Country, Spain
- Centro de Fı́sica de Materiales CFM-MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastian, Basque Country, Spain
- Departamento de Física de Materiales UPV/EHU, 20018 Donostia-San Sebastian, Basque Country, Spain
| | - Luis E Hueso
- CIC nanoGUNE BRTA, 20018 Donostia-San Sebastian, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
| | - F Sebastian Bergeret
- Donostia International Physics Center, 20018 Donostia-San Sebastian, Basque Country, Spain
- Centro de Fı́sica de Materiales CFM-MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastian, Basque Country, Spain
| | - Fèlix Casanova
- CIC nanoGUNE BRTA, 20018 Donostia-San Sebastian, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
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49
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Wang Z, Cheng H, Shi K, Liu Y, Qiao J, Zhu D, Cai W, Zhang X, Eimer S, Zhu D, Zhang J, Fert A, Zhao W. Modulation of field-like spin orbit torque in heavy metal/ferromagnet heterostructures. NANOSCALE 2020; 12:15246-15251. [PMID: 32643741 DOI: 10.1039/d0nr02762f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Spin orbit torque (SOT) has drawn widespread attention in the emerging field of magnetic memory devices, such as magnetic random access memory (MRAM). To promote the performance of SOT-MRAM, most efforts have been devoted to enhance the SOT switching efficiency by improving the damping-like torque. Recently, some studies noted that the field-like torque also plays a crucial role in the nanosecond-timescale SOT dynamics. However, there is not yet an effective way to tune its relative amplitude. Here, we experimentally modulate the field-like SOT in W/CoFeB/MgO trilayers through tuning the interfacial spin accumulation. By performing spin Hall magnetoresistance measurement, we find that the CoFeB with enhanced spin dephasing, either generated from larger layer thickness or from proper annealing, can distinctly boost the spin absorption and enhance the interfacial spin mixing conductance Gr. While the damping-like torque efficiency increases with Gr, the field-like torque efficiency is found to decrease with it. The results suggest that the interfacial spin accumulation, which largely contributes to the field-like torque, is reduced by higher interfacial spin transparency. Our work shows a new path to further improve the performance of SOT-based ultrafast magnetic devices.
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Affiliation(s)
- Zilu Wang
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China. and Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao, China and Hefei Innovation Research Institute, Beihang University, Hefei 230013, China
| | - Houyi Cheng
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China. and Hefei Innovation Research Institute, Beihang University, Hefei 230013, China
| | - Kewen Shi
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China.
| | - Yang Liu
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China.
| | - Junfeng Qiao
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China.
| | - Daoqian Zhu
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China.
| | - Wenlong Cai
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China.
| | - Xueying Zhang
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China. and Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao, China
| | - Sylvain Eimer
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China. and Hefei Innovation Research Institute, Beihang University, Hefei 230013, China
| | - Dapeng Zhu
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China. and Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao, China
| | - Jie Zhang
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China.
| | - Albert Fert
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China. and Unité Mixte de Physique, CNRS, Thales, University of Paris-Saclay, Palaiseau, France
| | - Weisheng Zhao
- Fert Beijing Institute, School of Microelectronics, Beijing Advanced Innovation Center for Big Data and Brain Computing, Beihang University, 100191, China. and Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao, China and Hefei Innovation Research Institute, Beihang University, Hefei 230013, China
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Kang MG, Go G, Kim KW, Choi JG, Park BG, Lee KJ. Negative spin Hall magnetoresistance of normal metal/ferromagnet bilayers. Nat Commun 2020; 11:3619. [PMID: 32681024 PMCID: PMC7367820 DOI: 10.1038/s41467-020-17463-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 06/27/2020] [Indexed: 11/21/2022] Open
Abstract
Interconversion between charge and spin through spin-orbit coupling lies at the heart of condensed-matter physics. In normal metal/ferromagnet bilayers, a concerted action of the interconversions, the spin Hall effect and its inverse effect of normal metals, results in spin Hall magnetoresistance, whose sign is always positive regardless of the sign of spin Hall conductivity of normal metals. Here we report that the spin Hall magnetoresistance of Ta/NiFe bilayers is negative, necessitating an additional interconversion process. Our theory shows that the interconversion owing to interfacial spin-orbit coupling at normal metal/ferromagnet interfaces can give rise to negative spin Hall magnetoresistance. Given that recent studies found the conversion from charge currents to spin currents at normal metal/ferromagnet interfaces, our work provides a missing proof of its reciprocal spin-current-to-charge-current conversion at same interface. Our result suggests that interfacial spin-orbit coupling effect can dominate over bulk effects, thereby demanding interface engineering for advanced spintronics devices.
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Affiliation(s)
- Min-Gu Kang
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Gyungchoon Go
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, Korea
| | - Kyoung-Whan Kim
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, 02792, Korea
| | - Jong-Guk Choi
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
| | - Byong-Guk Park
- Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea.
| | - Kyung-Jin Lee
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, Korea.
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Korea.
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