1
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Su SH, Huang TT, Pan BR, Lee JC, Qiu YJ, Chuang PY, Gultom P, Cheng CM, Chen YC, Huang JCA. Large Tunable Spin-to-Charge Conversion in Ni 80Fe 20/Molybdenum Disulfide by Cu Insertion. ACS APPLIED MATERIALS & INTERFACES 2024; 16. [PMID: 38670928 PMCID: PMC11082844 DOI: 10.1021/acsami.4c03360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/12/2024] [Accepted: 04/18/2024] [Indexed: 04/28/2024]
Abstract
Spin-to-charge conversion at the interface between magnetic materials and transition metal dichalcogenides has drawn great interest in the research efforts to develop fast and ultralow power consumption devices for spintronic applications. Here, we report room temperature observations of spin-to-charge conversion arising from the interface of Ni80Fe20 (Py) and molybdenum disulfide (MoS2). This phenomenon can be characterized by the inverse Edelstein effect length (λIEE), which is enhanced with decreasing MoS2 thicknesses, demonstrating the dominant role of spin-orbital coupling (SOC) in MoS2. The spin-to-charge conversion can be significantly improved by inserting a Cu interlayer between Py and MoS2, suggesting that the Cu interlayer can prevent magnetic proximity effect from the Py layer and protect the SOC on the MoS2 surface from exchange interactions with Py. Furthermore, the Cu-MoS2 interface can enhance the spin current and improve electronic transport. Our results suggest that tailoring the interface of magnetic heterostructures provides an alternative strategy for the development of spintronic devices to achieve higher spin-to-charge conversion efficiencies.
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Affiliation(s)
- Shu Hsuan. Su
- Department
of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Tzu Tai Huang
- Department
of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Bi-Rong Pan
- Department
of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Jung-Chuan Lee
- Department
of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Sheng
Chuang Technology Company, Taichung 407330, Taiwan
| | - Yi Jie Qiu
- Department
of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Pei-Yu Chuang
- National
Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Pangihutan Gultom
- Department
of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Cheng-Maw Cheng
- National
Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
- Department
of Photonics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Yi-Chun Chen
- Department
of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Jung-Chung Andrew Huang
- Department
of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Department
of Applied Physics, National University
of Kaohsiung, Kaohsiung 811726, Taiwan
- Taiwan Consortium
of Emergent Crystalline Materials, Ministry
of Science and Technology, Taipei 106, Taiwan
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2
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Huang X, Chen X, Li Y, Mangeri J, Zhang H, Ramesh M, Taghinejad H, Meisenheimer P, Caretta L, Susarla S, Jain R, Klewe C, Wang T, Chen R, Hsu CH, Harris I, Husain S, Pan H, Yin J, Shafer P, Qiu Z, Rodrigues DR, Heinonen O, Vasudevan D, Íñiguez J, Schlom DG, Salahuddin S, Martin LW, Analytis JG, Ralph DC, Cheng R, Yao Z, Ramesh R. Manipulating chiral spin transport with ferroelectric polarization. NATURE MATERIALS 2024:10.1038/s41563-024-01854-8. [PMID: 38622325 DOI: 10.1038/s41563-024-01854-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 03/07/2024] [Indexed: 04/17/2024]
Abstract
A magnon is a collective excitation of the spin structure in a magnetic insulator and can transmit spin angular momentum with negligible dissipation. This quantum of a spin wave has always been manipulated through magnetic dipoles (that is, by breaking time-reversal symmetry). Here we report the experimental observation of chiral spin transport in multiferroic BiFeO3 and its control by reversing the ferroelectric polarization (that is, by breaking spatial inversion symmetry). The ferroelectrically controlled magnons show up to 18% modulation at room temperature. The spin torque that the magnons in BiFeO3 carry can be used to efficiently switch the magnetization of adjacent magnets, with a spin-torque efficiency comparable to the spin Hall effect in heavy metals. Utilizing such controllable magnon generation and transmission in BiFeO3, an all-oxide, energy-scalable logic is demonstrated composed of spin-orbit injection, detection and magnetoelectric control. Our observations open a new chapter of multiferroic magnons and pave another path towards low-dissipation nanoelectronics.
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Affiliation(s)
- Xiaoxi Huang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Xianzhe Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Yuhang Li
- Department of Electrical and Computer Engineering, University of California, Riverside, CA, USA
| | - John Mangeri
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology, Esch/Alzette, Luxembourg
| | - Hongrui Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Maya Ramesh
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA
| | | | - Peter Meisenheimer
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Lucas Caretta
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Sandhya Susarla
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
| | - Rakshit Jain
- Department of Physics, Cornell University, Ithaca, NY, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
| | - Christoph Klewe
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Tianye Wang
- Department of Physics, University of California, Berkeley, CA, USA
| | - Rui Chen
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Cheng-Hsiang Hsu
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA
| | - Isaac Harris
- Department of Physics, University of California, Berkeley, CA, USA
| | - Sajid Husain
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Hao Pan
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Jia Yin
- Applied Mathematics and Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Ziqiang Qiu
- Department of Physics, University of California, Berkeley, CA, USA
| | - Davi R Rodrigues
- Department of Electrical Engineering, Politecnico di Bari, Bari, Italy
| | - Olle Heinonen
- Materials Science Division, Argonne National Laboratory, Lemont, IL, USA
| | - Dilip Vasudevan
- Applied Mathematics and Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jorge Íñiguez
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology, Esch/Alzette, Luxembourg
- Department of Physics and Materials Science, University of Luxembourg, Belvaux, Luxembourg
| | - Darrell G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA
| | - Sayeef Salahuddin
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - James G Analytis
- Department of Physics, University of California, Berkeley, CA, USA
- CIFAR Quantum Materials, CIFAR, Toronto, Ontario, Canada
| | - Daniel C Ralph
- Department of Physics, Cornell University, Ithaca, NY, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
| | - Ran Cheng
- Department of Electrical and Computer Engineering, University of California, Riverside, CA, USA
- Department of Physics and Astronomy, University of California, Riverside, CA, USA
| | - Zhi Yao
- Applied Mathematics and Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Department of Physics, University of California, Berkeley, CA, USA.
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3
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Kanistras N, Scheuer L, Anyfantis DI, Barnasas A, Torosyan G, Beigang R, Crisan O, Poulopoulos P, Papaioannou ET. Magnetic Properties and THz Emission from Co/CoO/Pt and Ni/NiO/Pt Trilayers. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:215. [PMID: 38276733 DOI: 10.3390/nano14020215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/02/2024] [Accepted: 01/12/2024] [Indexed: 01/27/2024]
Abstract
THz radiation emitted by ferromagnetic/non-magnetic bilayers is a new emergent field in ultra-fast spin physics phenomena with a lot of potential for technological applications in the terahertz (THz) region of the electromagnetic spectrum. The role of antiferromagnetic layers in the THz emission process is being heavily investigated at the moment. In this work, we fabricate trilayers in the form of Co/CoO/Pt and Ni/NiO/Pt with the aim of studying the magnetic properties and probing the role of very thin antiferromagnetic interlayers like NiO and CoO in transporting ultrafast spin current. First, we reveal the static magnetic properties of the samples by using temperature-dependent Squid magnetometry and then we quantify the dynamic properties with the help of ferromagnetic resonance spectroscopy. We show magnetization reversal that has large exchange bias values and we extract enhanced damping values for the trilayers. THz time-domain spectroscopy examines the influence of the antiferromagnetic interlayer in the THz emission, showing that the NiO interlayer in particular is able to transport spin current.
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Affiliation(s)
- Nikolaos Kanistras
- Institute of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann Platz 3, 06120 Halle, Germany
| | - Laura Scheuer
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany
| | - Dimitrios I Anyfantis
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece
| | - Alexandros Barnasas
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece
| | - Garik Torosyan
- Photonik Center Kaiserslautern, 67663 Kaiserslautern, Germany
| | - René Beigang
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany
| | - Ovidiu Crisan
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania
| | - Panagiotis Poulopoulos
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece
| | - Evangelos Th Papaioannou
- Institute of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann Platz 3, 06120 Halle, Germany
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania
- Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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4
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Zhou Y, Guo T, Han L, Liao L, He W, Wan C, Chen C, Wang Q, Qiao L, Bai H, Zhu W, Zhang Y, Chen R, Han X, Pan F, Song C. Spin-torque-driven antiferromagnetic resonance. SCIENCE ADVANCES 2024; 10:eadk7935. [PMID: 38215195 PMCID: PMC10786412 DOI: 10.1126/sciadv.adk7935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 12/14/2023] [Indexed: 01/14/2024]
Abstract
The intrinsic fast dynamics make antiferromagnetic spintronics a promising avenue for faster data processing. Ultrafast antiferromagnetic resonance-generated spin current provides valuable access to antiferromagnetic spin dynamics. However, the inverse effect, spin-torque-driven antiferromagnetic resonance (ST-AFMR), which is attractive for practical utilization of fast devices but seriously impeded by difficulties in controlling and detecting Néel vectors, remains elusive. We observe ST-AFMR in Y3Fe5O12/α-Fe2O3/Pt at room temperature. The Néel vector oscillates and contributes to voltage signal owing to antiferromagnetic negative spin Hall magnetoresistance-induced spin rectification effect, which has the opposite sign to ferromagnets. The Néel vector in antiferromagnetic α-Fe2O3 is strongly coupled to the magnetization in Y3Fe5O12 buffer, resulting in the convenient control of Néel vectors. ST-AFMR experiment is bolstered by micromagnetic simulations, where both the Néel vector and the canted moment of α-Fe2O3 are in elliptic resonance. These findings shed light on the spin current-induced dynamics in antiferromagnets and represent a step toward electrically controlled antiferromagnetic terahertz emitters.
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Affiliation(s)
- Yongjian Zhou
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Tingwen Guo
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
- LSI, CEA/DRF/IRAMIS, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, F-91128 Palaiseau, France
| | - Lei Han
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Liyang Liao
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Wenqing He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Caihua Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Chong Chen
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Qian Wang
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Leilei Qiao
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Hua Bai
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Wenxuan Zhu
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Yichi Zhang
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Ruyi Chen
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Feng Pan
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Cheng Song
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
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5
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Poelchen G, Hellwig J, Peters M, Usachov DY, Kliemt K, Laubschat C, Echenique PM, Chulkov EV, Krellner C, Parkin SSP, Vyalikh DV, Ernst A, Kummer K. Long-lived spin waves in a metallic antiferromagnet. Nat Commun 2023; 14:5422. [PMID: 37669952 PMCID: PMC10480465 DOI: 10.1038/s41467-023-40963-x] [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: 01/15/2023] [Accepted: 08/17/2023] [Indexed: 09/07/2023] Open
Abstract
Collective spin excitations in magnetically ordered crystals, called magnons or spin waves, can serve as carriers in novel spintronic devices with ultralow energy consumption. The generation of well-detectable spin flows requires long lifetimes of high-frequency magnons. In general, the lifetime of spin waves in a metal is substantially reduced due to a strong coupling of magnons to the Stoner continuum. This makes metals unattractive for use as components for magnonic devices. Here, we present the metallic antiferromagnet CeCo2P2, which exhibits long-living magnons even in the terahertz (THz) regime. For CeCo2P2, our first-principle calculations predict a suppression of low-energy spin-flip Stoner excitations, which is verified by resonant inelastic X-ray scattering measurements. By comparison to the isostructural compound LaCo2P2, we show how small structural changes can dramatically alter the electronic structure around the Fermi level leading to the classical picture of the strongly damped magnons intrinsic to metallic systems. Our results not only demonstrate that long-lived magnons in the THz regime can exist in bulk metallic systems, but they also open a path for an efficient search for metallic magnetic systems in which undamped THz magnons can be excited.
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Affiliation(s)
- G Poelchen
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043, Grenoble, France.
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062, Dresden, Germany.
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187, Dresden, Germany.
| | - J Hellwig
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438, Frankfurt am Main, Germany
| | - M Peters
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438, Frankfurt am Main, Germany
| | - D Yu Usachov
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain
| | - K Kliemt
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438, Frankfurt am Main, Germany
| | - C Laubschat
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062, Dresden, Germany
| | - P M Echenique
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - E V Chulkov
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, 20018, Donostia-San Sebastián, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, 20080, Donostia-San Sebastián, Spain
| | - C Krellner
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438, Frankfurt am Main, Germany
| | - S S P Parkin
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany
| | - D V Vyalikh
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - A Ernst
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany
- Institut für Theoretische Physik, Johannes Kepler Universität, 4040, Linz, Austria
| | - K Kummer
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043, Grenoble, France.
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6
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Gao T, Qaiumzadeh A, Troncoso RE, Haku S, An H, Nakayama H, Tazaki Y, Zhang S, Tu R, Asami A, Brataas A, Ando K. Impact of inherent energy barrier on spin-orbit torques in magnetic-metal/semimetal heterojunctions. Nat Commun 2023; 14:5187. [PMID: 37626028 PMCID: PMC10457350 DOI: 10.1038/s41467-023-40876-9] [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: 09/03/2022] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
Spintronic devices are based on heterojunctions of two materials with different magnetic and electronic properties. Although an energy barrier is naturally formed even at the interface of metallic heterojunctions, its impact on spin transport has been overlooked. Here, using diffusive spin Hall currents, we provide evidence that the inherent energy barrier governs the spin transport even in metallic systems. We find a sizable field-like torque, much larger than the damping-like counterpart, in Ni81Fe19/Bi0.1Sb0.9 bilayers. This is a distinct signature of barrier-mediated spin-orbit torques, which is consistent with our theory that predicts a strong modification of the spin mixing conductance induced by the energy barrier. Our results suggest that the spin mixing conductance and the corresponding spin-orbit torques are strongly altered by minimizing the work function difference in the heterostructure. These findings provide a new mechanism to control spin transport and spin torque phenomena by interfacial engineering of metallic heterostructures.
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Affiliation(s)
- Tenghua Gao
- Keio Institute of Pure and Applied Science, Keio University, Yokohama, 223-8522, Japan
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama, 223-8522, Japan
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, China
| | - Alireza Qaiumzadeh
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491, Trondheim, Norway
| | - Roberto E Troncoso
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491, Trondheim, Norway
- School of Engineering and Sciences, Universidad Adolfo Ibáñez, Santiago, Chile
| | - Satoshi Haku
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama, 223-8522, Japan
| | - Hongyu An
- College of New Materials and New Energies, Shenzhen Technology University, Shenzhen, 518118, China
| | - Hiroki Nakayama
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama, 223-8522, Japan
| | - Yuya Tazaki
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama, 223-8522, Japan
| | - Song Zhang
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, China
| | - Rong Tu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, China
| | - Akio Asami
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama, 223-8522, Japan
| | - Arne Brataas
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491, Trondheim, Norway
| | - Kazuya Ando
- Keio Institute of Pure and Applied Science, Keio University, Yokohama, 223-8522, Japan.
- Department of Applied Physics and Physico-Informatics, Keio University, Yokohama, 223-8522, Japan.
- Center for Spintronics Research Network, Keio University, Yokohama, 223-8522, Japan.
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7
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Cao L, Huang Z, Gong Y, Guo Q, Jalali M, Du J, Xu Y, Chen Q, Lu X, Zhai Y. Magnetic field modulated ultrafast spin dynamics at Ni 80Fe 20/Neodymium interface. OPTICS EXPRESS 2023; 31:21731-21738. [PMID: 37381263 DOI: 10.1364/oe.489472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 04/27/2023] [Indexed: 06/30/2023]
Abstract
Ultrafast spin dynamics is crucial for the next-generation spintronic devices towards high-speed data processing. Here, we investigate the ultrafast spin dynamics of Neodymium/Ni80Fe20 (Nd/Py) bilayers by the time-resolved magneto-optical Kerr effect. The effective modulation of spin dynamics at Nd/Py interfaces is realized by an external magnetic field. The effective magnetic damping of Py increases with increasing Nd thickness, and a large spin mixing conductance (∼19.35×1015 cm-2) at Nd/Py interface is obtained, representing the robust spin pumping effect by Nd/Py interface. The tuning effects are suppressed at a high magnetic field due to the reduced antiparallel magnetic moments at Nd/Py interface. Our results contribute to understanding ultrafast spin dynamics and spin transport behavior in high-speed spintronic devices.
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8
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Han J, Cheng R, Liu L, Ohno H, Fukami S. Coherent antiferromagnetic spintronics. NATURE MATERIALS 2023; 22:684-695. [PMID: 36941390 DOI: 10.1038/s41563-023-01492-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 01/25/2023] [Indexed: 06/03/2023]
Abstract
Antiferromagnets have attracted extensive interest as a material platform in spintronics. So far, antiferromagnet-enabled spin-orbitronics, spin-transfer electronics and spin caloritronics have formed the bases of antiferromagnetic spintronics. Spin transport and manipulation based on coherent antiferromagnetic dynamics have recently emerged, pushing the developing field of antiferromagnetic spintronics towards a new stage distinguished by the features of spin coherence. In this Review, we categorize and analyse the critical effects that harness the coherence of antiferromagnets for spintronic applications, including spin pumping from monochromatic antiferromagnetic magnons, spin transmission via phase-correlated antiferromagnetic magnons, electrically induced spin rotation and ultrafast spin-orbit effects in antiferromagnets. We also discuss future opportunities in research and applications stimulated by the principles, materials and phenomena of coherent antiferromagnetic spintronics.
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Affiliation(s)
- Jiahao Han
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan.
| | - Ran Cheng
- Department of Electrical and Computer Engineering, University of California Riverside, Riverside, CA, USA
- Department of Physics and Astronomy, University of California Riverside, Riverside, CA, USA
| | - Luqiao Liu
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Hideo Ohno
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, Sendai, Japan
- Center for Innovative Integrated Electronic Systems, Tohoku University, Sendai, Japan
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
| | - Shunsuke Fukami
- Research Institute of Electrical Communication, Tohoku University, Sendai, Japan.
- Center for Science and Innovation in Spintronics, Tohoku University, Sendai, Japan.
- Center for Innovative Integrated Electronic Systems, Tohoku University, Sendai, Japan.
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan.
- Inamori Research Institute of Science, Kyoto, Japan.
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9
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Zheng D, Lan J, Fang B, Li Y, Liu C, Ledesma-Martin JO, Wen Y, Li P, Zhang C, Ma Y, Qiu Z, Liu K, Manchon A, Zhang X. High-Efficiency Magnon-Mediated Magnetization Switching in All-Oxide Heterostructures with Perpendicular Magnetic Anisotropy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2203038. [PMID: 35776842 DOI: 10.1002/adma.202203038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/30/2022] [Indexed: 06/15/2023]
Abstract
The search for efficient approaches to realize local switching of magnetic moments in spintronic devices has attracted extensive attention. One of the most promising approaches is the electrical manipulation of magnetization through electron-mediated spin torque. However, the Joule heat generated via electron motion unavoidably causes substantial energy dissipation and potential damage to spintronic devices. Here, all-oxide heterostructures of SrRuO3 /NiO/SrIrO3 are epitaxially grown on SrTiO3 single-crystal substrates following the order of the ferromagnetic transition metal oxide SrRuO3 with perpendicular magnetic anisotropy, insulating and antiferromagnetic NiO, and metallic transition metal oxide SrIrO3 with strong spin-orbit coupling. It is demonstrated that instead of the electron spin torques, the magnon torques present in the antiferromagnetic NiO layer can directly manipulate the perpendicular magnetization of the ferromagnetic layer. This magnon mechanism may significantly reduce the electron motion-related energy dissipation from electron-mediated spin currents. Interestingly, the threshold current density to generate a sufficient magnon current to manipulate the magnetization is one order of magnitude smaller than that in conventional metallic systems. These findings suggest a route for developing highly efficient all-oxide spintronic devices operated by magnon current.
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Affiliation(s)
- Dongxing Zheng
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Jin Lan
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Processing Technology, Institute of Advanced Materials Physics, School of Science, Tianjin University, Tianjin, 300350, China
| | - Bin Fang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Yan Li
- 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
| | - J Omar Ledesma-Martin
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Yan Wen
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Peng Li
- 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
| | - Yinchang Ma
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Ziqiang Qiu
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720, USA
| | - Kai Liu
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | | | - Xixiang Zhang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
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10
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Mutual spin-phonon driving effects and phonon eigenvector renormalization in nickel (II) oxide. Proc Natl Acad Sci U S A 2022; 119:e2120553119. [PMID: 35858352 PMCID: PMC9304033 DOI: 10.1073/pnas.2120553119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The physics of mutual interaction of phonon quasiparticles with electronic spin degrees of freedom, leading to unusual transport phenomena of spin and heat, has been a subject of continuing interests for decades. Despite its pivotal role in transport processes, the effect of spin-phonon coupling on the phonon system, especially acoustic phonon properties, has so far been elusive. By means of inelastic neutron scattering and first-principles calculations, anomalous scattering spectral intensity from acoustic phonons was identified in the exemplary collinear antiferromagnetic nickel (II) oxide, unveiling strong spin-lattice correlations that renormalize the polarization of acoustic phonon. In particular, a clear magnetic scattering signature of the measured neutron scattering intensity from acoustic phonons is demonstrated by its momentum transfer and temperature dependences. The anomalous scattering intensity is successfully modeled with a modified magneto-vibrational scattering cross-section, suggesting the presence of spin precession driven by phonon. The renormalization of phonon eigenvector is indicated by the observed "geometry-forbidden" neutron scattering intensity from transverse acoustic phonon. Importantly, the eigenvector renormalization cannot be explained by magnetostriction but instead, it could result from the coupling between phonon and local magnetization of ions.
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11
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Orthogonal interlayer coupling in an all-antiferromagnetic junction. Nat Commun 2022; 13:3723. [PMID: 35764620 PMCID: PMC9240048 DOI: 10.1038/s41467-022-31531-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 06/22/2022] [Indexed: 11/21/2022] Open
Abstract
In conventional ferromagnet/spacer/ferromagnet sandwiches, noncollinear couplings are commonly absent because of the low coupling energy and strong magnetization. For antiferromagnets (AFM), the small net moment can embody a low coupling energy as a sizable coupling field, however, such AFM sandwich structures have been scarcely explored. Here we demonstrate orthogonal interlayer coupling at room temperature in an all-antiferromagnetic junction Fe2O3/Cr2O3/Fe2O3, where the Néel vectors in the top and bottom Fe2O3 layers are strongly orthogonally coupled and the coupling strength is significantly affected by the thickness of the antiferromagnetic Cr2O3 spacer. From the energy and symmetry analysis, the direct coupling via uniform magnetic ordering in Cr2O3 spacer in our junction is excluded. The coupling is proposed to be mediated by the non-uniform domain wall state in the spacer. The strong long-range coupling in an antiferromagnetic junction provides an unexplored approach for designing antiferromagnetic structures and makes it a promising building block for antiferromagnetic devices. Ferromagnet/spacer/ferromagnet sandwiches have been studied extensively, and used in a variety of spintronic devices. Here, Zhou et al. create an all anti-ferromagnetic sandwich of Fe2O3/Cr2O3/Fe2O3, and demonstrate strong orthogonal coupling between the top and bottom Fe2O3 layers.
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12
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Zhou Y, Guo T, Qiao L, Wang Q, Zhu M, Zhang J, Liu Q, Zhao M, Wan C, He W, Bai H, Han L, Huang L, Chen R, Zhao Y, Han X, Pan F, Song C. Piezoelectric Strain-Controlled Magnon Spin Current Transport in an Antiferromagnet. NANO LETTERS 2022; 22:4646-4653. [PMID: 35583209 DOI: 10.1021/acs.nanolett.2c00405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
As the core of spintronics, the transport of spin aims at a low-dissipation data process. The pure spin current transmission carried by magnons in antiferromagnetic insulators is natively endowed with superiority such as long-distance propagation and ultrafast speed. However, the traditional control of magnon transport in an antiferromagnet via a magnetic field or temperature variation adds critical inconvenience to practical applications. Controlling magnon transport by electric methods is a promising way to overcome such embarrassment and to promote the development of energy-efficient antiferromagnetic logic. Here, the experimental realization of an electric field-induced piezoelectric strain-controlled magnon spin current transmission through the antiferromagnetic insulator in the Y3Fe5O12/Cr2O3/Pt trilayer is reported. An efficient and nonvolatile manipulation of magnon propagation/blocking is achieved by changing the relative direction between the Néel vector and spin polarization, which is tuned by ferroelastic strain from the piezoelectric substrate. The piezoelectric strain-controlled antiferromagnetic magnon transport opens an avenue for the exploitation of antiferromagnet-based spin/magnon transistors with ultrahigh energy efficiency.
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Affiliation(s)
- Yongjian Zhou
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Tingwen Guo
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Leilei Qiao
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Qian Wang
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Meng Zhu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jia Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Quan Liu
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Mingkun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Caihua Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wenqing He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hua Bai
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Lei Han
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Lin Huang
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Ruyi Chen
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Yonggang Zhao
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Feng Pan
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Cheng Song
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
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13
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Wu PH, Qu D, Tu YC, Lin YZ, Chien CL, Huang SY. Exploiting Spin Fluctuations for Enhanced Pure Spin Current. PHYSICAL REVIEW LETTERS 2022; 128:227203. [PMID: 35714236 DOI: 10.1103/physrevlett.128.227203] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 02/13/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
We demonstrate the interplay of pure spin current, spin-polarized current, and spin fluctuation in 3d Ni_{x}Cu_{1-x}. By tuning the compositions of the Ni_{x}Cu_{1-x} alloys, we separate the effects due to the pure spin current and spin-polarized current. By exploiting the interaction of spin current with spin fluctuation in suitable Ni-Cu alloys, we obtain an unprecedentedly high spin Hall angle of 46%, about 5 times larger than that in Pt, at room temperature. Furthermore, we show that spin-dependent thermal transport via anomalous Nernst effect can serve as a sensitive magnetometer to electrically probe the magnetic phase transitions in thin films with in-plane anisotropy. The enhancement of spin Hall angle by exploiting spin current fluctuation via composition control makes 3d magnets functional materials in charge-to-spin conversion for spintronic application.
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Affiliation(s)
- Po-Hsun Wu
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Danru Qu
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Yen-Chang Tu
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Yin-Ze Lin
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - C L Chien
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Ssu-Yen Huang
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
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14
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Zhu D, Zhang T, Fu X, Hao R, Hamzić A, Yang H, Zhang X, Zhang H, Du A, Xiong D, Shi K, Yan S, Zhang S, Fert A, Zhao W. Sign Change of Spin-Orbit Torque in Pt/NiO/CoFeB Structures. PHYSICAL REVIEW LETTERS 2022; 128:217702. [PMID: 35687442 DOI: 10.1103/physrevlett.128.217702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 01/30/2022] [Accepted: 04/20/2022] [Indexed: 06/15/2023]
Abstract
Antiferromagnetic insulators have recently been proved to support spin current efficiently. Here, we report the dampinglike spin-orbit torque (SOT) in Pt/NiO/CoFeB has a strong temperature dependence and reverses the sign below certain temperatures, which is different from the slight variation with temperature in the Pt/CoFeB bilayer. The negative dampinglike SOT at low temperatures is proposed to be mediated by the magnetic interactions that tie with the "exchange bias" in Pt/NiO/CoFeB, in contrast to the thermal-magnon-mediated scenario at high temperatures. Our results highlight the promise to control the SOT through tuning the magnetic structure in multilayers.
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Affiliation(s)
- 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
| | - Tianrui Zhang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
| | - Xiao Fu
- 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
| | - 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
| | - Amir Hamzić
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
- Department of Physics, Faculty of Science, University of Zagreb, Zagreb HR-10001, Croatia
| | - Huaiwen Yang
- 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
| | - 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
| | - Hui Zhang
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
| | - Ao Du
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
| | - Danrong Xiong
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
| | - Kewen Shi
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
| | - Shishen Yan
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Shufeng Zhang
- Department of Physics, University of Arizona, Tucson, Arizona 85721, USA
| | - Albert Fert
- Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau 91767, France
| | - 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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15
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Lee K, Lee DK, Yang D, Mishra R, Kim DJ, Liu S, Xiong Q, Kim SK, Lee KJ, Yang H. Superluminal-like magnon propagation in antiferromagnetic NiO at nanoscale distances. NATURE NANOTECHNOLOGY 2021; 16:1337-1341. [PMID: 34697489 DOI: 10.1038/s41565-021-00983-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Magnon-mediated angular-momentum flow in antiferromagnets may become a design element for energy-efficient, low-dissipation and high-speed spintronic devices1,2. Owing to their low energy dissipation, antiferromagnetic magnons can propagate over micrometre distances3. However, direct observation of their high-speed propagation has been elusive due to the lack of sufficiently fast probes2. Here we measure the antiferromagnetic magnon propagation in the time domain at the nanoscale (≤50 nm) with optical-driven terahertz emission. In non-magnetic-Bi2Te3/antiferromagnetic-insulator-NiO/ferromagnetic-Co trilayers, we observe a magnon velocity of ~650 km s-1 in the NiO layer. This velocity far exceeds previous estimations of the maximum magnon group velocity of ~40 km s-1, which were based on the magnon dispersion measurements of NiO using inelastic neutron scattering4,5. Our theory suggests that for magnon propagation at the nanoscale, a finite damping makes the dispersion anomalous for small magnon wavenumbers and yields a superluminal-like magnon velocity. Given the generality of finite dissipation in materials, our results strengthen the prospects of ultrafast nanodevices using antiferromagnetic magnons.
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Affiliation(s)
- Kyusup Lee
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Dong-Kyu Lee
- Department of Materials Science and Engineering, Korea University, Seoul, Korea
| | - Dongsheng Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Rahul Mishra
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
- Centre for Applied Research in Electronics, Indian Institute of Technology Delhi, New Delhi, India
| | - Dong-Jun Kim
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Sheng Liu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Qihua Xiong
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, P. R. China
- Beijing Academy of Quantum Information Sciences, Beijing, P. R. China
- Beijing Innovation Center for Future Chips, Tsinghua University, Beijing, P. R. China
| | - Se Kwon Kim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Kyung-Jin Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
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16
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Omelchenko P, Montoya EA, Girt E, Heinrich B. Observation of Pure-Spin-Current Diodelike Effect at the Au/Pt Interface. PHYSICAL REVIEW LETTERS 2021; 127:137201. [PMID: 34623852 DOI: 10.1103/physrevlett.127.137201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 05/31/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
Asymmetric charge transport at the interface of two materials with dissimilar electrical properties, such as metal-semiconductor and p-n junctions, is the fundamental feature behind modern diode and transistor technology. Spin pumping from a ferromagnet into an adjacent nonmagnetic material is a powerful technique to generate pure-spin currents, wherein spin transport is unaccompanied by net charge transport. It is therefore interesting to study pure-spin transport at the interface of two materials with different spin transport properties. Here we demonstrate asymmetric transport of pure-spin currents across an interface of dissimilar nonmagnetic materials Au/Pt. We exploit Py/Au/Pt/Co structures where spin pumping can generate pure-spin current from either Py or Co independently. We find that the transmission of pure-spin current from Au into Pt is twice as efficient as transmission from Pt into Au. Experimental results are interpreted by extending conventional spin-pumping, spin-diffusion theory to include boundary conditions of reflected and transmitted spin current at the Au/Pt interface that are proportional to the established spin chemical potentials on either side of the interface.
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Affiliation(s)
- Pavlo Omelchenko
- Department of Physics, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
| | - Eric Arturo Montoya
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
| | - Erol Girt
- Department of Physics, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
| | - Bret Heinrich
- Department of Physics, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
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17
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Stebliy ME, Kolesnikov AG, Bazrov MA, Letushev ME, Ognev AV, Davydenko AV, Stebliy EV, Kozlov AG, Wang X, Wan C, Fang C, Zhao M, Han X, Samardak AS. Current-Induced Manipulation of the Exchange Bias in a Pt/Co/NiO Structure. ACS APPLIED MATERIALS & INTERFACES 2021; 13:42258-42265. [PMID: 34427434 DOI: 10.1021/acsami.1c12683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
An experimental study of the phenomenon of electric current influence on the value and orientation of the exchange bias field (HEB) in the Pt/Co/NiO structure is carried out. Depending on the direction of the magnetization in a ferromagnet (FM) layer and the current pulse amplitude, the value of the HEB field can be changed repeatedly in the range of ±7.5 mT. A few experiments are performed to separate the contributions from two current-induced effects: (i) an injection of the spin current into an antiferromagnet layer (AFM) and (ii) Joule heating. As a result, we conclude that the modification in the HEB field during current pulse transmission in the Pt/Co/NiO structure is due to heating and the low value of Néel temperature (TN = 162 °C). This fact explains the absence of the exchange bias effect on the spin-orbit torque (SOT)-assisted magnetization switching. The most striking observation to emerge from the experimental data analysis is that depending on the initial spin configuration of the domain structure in the FM layer and the current pulse amplitude, the exchange bias can be changed locally. This opens up prospects for creating exchange-coupled FM/AFM structures with dynamically tuned parameters of the exchange bias, which can be used for the development of magnetic memory, neuromorphic, and logic devices based on magnetic nanosystems.
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Affiliation(s)
- Maksim E Stebliy
- School of Natural Sciences, Far Eastern Federal University, Vladivostok 690922, Russia
| | | | - Michail A Bazrov
- School of Natural Sciences, Far Eastern Federal University, Vladivostok 690922, Russia
| | - Michail E Letushev
- School of Natural Sciences, Far Eastern Federal University, Vladivostok 690922, Russia
| | - Alexey V Ognev
- School of Natural Sciences, Far Eastern Federal University, Vladivostok 690922, Russia
| | - Aleksandr V Davydenko
- School of Natural Sciences, Far Eastern Federal University, Vladivostok 690922, Russia
| | - Ekaterina V Stebliy
- School of Natural Sciences, Far Eastern Federal University, Vladivostok 690922, Russia
| | - Aleksei G Kozlov
- School of Natural Sciences, Far Eastern Federal University, Vladivostok 690922, Russia
| | - Xiao Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Caihua Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chi Fang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Mingkun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Alexander S Samardak
- School of Natural Sciences, Far Eastern Federal University, Vladivostok 690922, Russia
- National Research South Ural State University, Chelyabinsk 454080, Russia
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18
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Abstract
Antiferromagnetic oxides have recently gained much attention because of the possibility to manipulate electrically and optically the Néel vectors in these materials. Their ultrafast spin dynamics, long spin diffusion length and immunity to large magnetic fields make them attractive candidates for spintronic applications. Additionally, there have been many studies on spin wave and magnon transport in single crystals of these oxides. However, the successful applications of the antiferromagnetic oxides will require similar spin transport properties in thin films. In this work, we systematically show the sputtering deposition method for two uniaxial antiferromagnetic oxides, namely Cr2O3 and α-Fe2O3, on A-plane sapphire substrates, and identify the optimized deposition conditions for epitaxial films with low surface roughness. We also confirm the antiferromagnetic properties of the thin films. The deposition method developed in this article will be important for studying the magnon transport in these epitaxial antiferromagnetic thin films.
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19
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Fan Y, Finley J, Han J, Holtz ME, Quarterman P, Zhang P, Safi TS, Hou JT, Grutter AJ, Liu L. Resonant Spin Transmission Mediated by Magnons in a Magnetic Insulator Multilayer Structure. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2008555. [PMID: 33899284 DOI: 10.1002/adma.202008555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/15/2021] [Indexed: 06/12/2023]
Abstract
While being electrically insulating, magnetic insulators can behave as good spin conductors by carrying spin current with excited spin waves. So far, magnetic insulators are utilized in multilayer heterostructures for optimizing spin transport or to form magnon spin valves for reaching controls over the spin flow. In these studies, it remains an intensively visited topic as to what the corresponding roles of coherent and incoherent magnons are in the spin transmission. Meanwhile, understanding the underlying mechanism associated with spin transmission in insulators can help to identify new mechanisms that can further improve the spin transport efficiency. Here, by studying spin transport in a magnetic-metal/magnetic-insulator/platinum multilayer, it is demonstrated that coherent magnons can transfer spins efficiently above the magnon bandgap of magnetic insulators. Particularly the standing spin-wave mode can greatly enhance the spin flow by inducing a resonant magnon transmission. Furthermore, within the magnon bandgap, a shutdown of spin transmission due to the blocking of coherent magnons is observed. The demonstrated magnon transmission enhancement and filtering effect provides an efficient method for modulating spin current in magnonic devices.
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Affiliation(s)
- Yabin Fan
- Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Joseph Finley
- Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Jiahao Han
- Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Megan E Holtz
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Patrick Quarterman
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Pengxiang Zhang
- Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Taqiyyah S Safi
- Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Justin T Hou
- Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Alexander J Grutter
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Luqiao Liu
- Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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20
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Zhu L, Zhu L, Buhrman RA. Fully Spin-Transparent Magnetic Interfaces Enabled by the Insertion of a Thin Paramagnetic NiO Layer. PHYSICAL REVIEW LETTERS 2021; 126:107204. [PMID: 33784166 DOI: 10.1103/physrevlett.126.107204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/24/2020] [Accepted: 02/16/2021] [Indexed: 06/12/2023]
Abstract
Spin backflow and spin-memory loss have been well established to considerably lower the interfacial spin transmissivity of metallic magnetic interfaces and thus the energy efficiency of spin-orbit torque technologies. Here, we report that spin backflow and spin-memory loss at Pt-based heavy metal-ferromagnet interfaces can be effectively eliminated by inserting an insulating paramagnetic NiO layer of optimum thickness. The latter enables the thermal magnon-mediated essentially unity spin-current transmission at room temperature due to considerably enhanced effective spin-mixing conductance of the interface. As a result, we obtain dampinglike spin-orbit torque efficiency per unit current density of up to 0.8 as detected by the standard technology ferromagnet FeCoB and others, which reaches the expected upper-limit spin Hall ratio of Pt. We establish that Pt/NiO and Pt-Hf/NiO are two energy-efficient, integration-friendly, and high-endurance spin-current generators that provide >100 times greater energy efficiency than sputter-deposited topological insulators BiSb and BiSe. Our finding will benefit spin-orbitronic research and advance spin-torque technologies.
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Affiliation(s)
- Lijun Zhu
- Cornell University, Ithaca, New York 14850, USA
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China
| | - Lujun Zhu
- College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China
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21
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Strong Interfacial Perpendicular Magnetic Anisotropy in Exchange-Biased NiO/Co/Au and NiO/Co/NiO Layered Systems. MATERIALS 2021; 14:ma14051237. [PMID: 33807937 PMCID: PMC7961461 DOI: 10.3390/ma14051237] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 01/28/2023]
Abstract
The ability to induce and control the perpendicular magnetic anisotropy (PMA) of ferromagnetic layers has been widely investigated, especially those that offer additional functionalities (e.g., skyrmion stabilization, voltage-based magnetization switching, rapid propagation of domain walls). Out-of-plane magnetized ferromagnetic layers in direct contact with an oxide belong to this class. Nowadays, investigation of this type of system includes antiferromagnetic oxides (AFOs) because of their potential for new approaches to applied spintronics that exploit the exchange bias (EB) coupling between the ferromagnetic and the AFO layer. Here, we investigate PMA and EB effect in NiO/Co/Au and NiO/Co/NiO layered systems. We show that the coercive and EB fields increase significantly when the Co layer is coupled with two NiO layers, instead of one. Surrounding the Co layer only with NiO layers induces a strong PMA resulting in an out-of-plane magnetized system can be obtained without a heavy metal/ferromagnetic interface. The PMA arises from a significant surface contribution (0.74 mJ/m2) that can be enhanced up to 0.99 mJ/m2 by annealing at moderate temperatures (~450 K). Using field cooling processes for both systems, we demonstrate a wide-ranging control of the exchange bias field without perturbing other magnetic properties of importance.
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22
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Aryal S, Paudyal D, Pati R. Cr-Doped Ge-Core/Si-Shell Nanowire: An Antiferromagnetic Semiconductor. NANO LETTERS 2021; 21:1856-1862. [PMID: 33577344 DOI: 10.1021/acs.nanolett.0c04971] [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
An antiferromagnet offers many important functionalities such as opportunities for electrical control of magnetic domains, immunity from magnetic perturbations, and fast spin dynamics. Introducing some of these intriguing features of an antiferromagnet into a low dimensional semiconductor core-shell nanowire offers an exciting pathway for its usage in antiferromagnetic semiconductor spintronics. Here, using a quantum mechanical approach, we predict that the Cr-doped Ge-core/Si-shell nanowire behaves as an antiferromagnetic semiconductor. The origin of antiferromagnetic spin alignments between Cr is attributed to the superexchange interaction mediated by the pz orbitals of the Ge atoms that are bonded to Cr. A weak spin-orbit interaction was found in this material, suggesting a longer spin coherence length. The spin-dependent quantum transport calculations in the Cr-doped nanowire junction reveals a switching feature with a high ON/OFF current ratio (∼41 times higher for the ON state at a relatively small bias of 0.83 V).
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Affiliation(s)
- Sandip Aryal
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Durga Paudyal
- The Ames Laboratory, U.S. Department of Energy, Iowa State University, Ames, Iowa 50011, United States
- Electrical and Computer Engineering Department, Iowa State University, Ames, Iowa 50011, United States
| | - Ranjit Pati
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, United States
- Henes Center for Quantum Phenomena, Michigan Technological University, Houghton, Michigan 49931, United States
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23
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Mandziak A, Soria GD, Prieto JE, Foerster M, de la Figuera J, Aballe L. Different spin axis orientation and large antiferromagnetic domains in Fe-doped NiO/Ru(0001) epitaxial films. NANOSCALE 2020; 12:21225-21233. [PMID: 33057545 DOI: 10.1039/d0nr05756h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We present a spatially resolved X-ray magnetic dichroism study of high-quality, in situ grown nickel oxide films. NiO thin films were deposited on a Ru(0001) substrate by high temperature oxygen-assisted molecular beam epitaxy. We found that by adding a small amount of Fe, the growth mode can be modified in order to promote the formation of micron-sized, triangular islands. The morphology, shape, crystal structure and composition are determined by low-energy electron microscopy and diffraction, and synchrotron based X-ray absorption spectromicroscopy. The element specific XMLD measurements reveal strong antiferromagnetic contrast at room temperature and domains with up to micron sizes, reflecting the high structural quality of the islands. By means of vectorial magnetometry, the spin axis orientation was determined with nanometer spatial resolution, and found to depend on the relative orientation of the film and substrate lattices.
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Affiliation(s)
- Anna Mandziak
- Alba Synchrotron Light Facility, CELLS, Barcelona E-08290, Spain.
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24
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Scatena R, Montisci F, Lanza A, Casati NPM, Macchi P. Magnetic Network on Demand: Pressure Tunes Square Lattice Coordination Polymers Based on {[Cu(pyrazine) 2] 2+} n. Inorg Chem 2020; 59:10091-10098. [PMID: 32615765 PMCID: PMC8008383 DOI: 10.1021/acs.inorgchem.0c01229] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the pressure-induced structural and magnetic changes in [CuCl(pyz)2](BF4) (pyz = pyrazine) and [CuBr(pyz)2](BF4), two members of a family of three-dimensional coordination polymers based on square mesh {[Cu(pyz)2]2+}n layers. High-pressure X-ray diffraction and density functional theory calculations have been used to investigate the structure-magnetic property relationship. Although structurally robust and almost undeformed within a large pressure range, the {[Cu(pyz)2]2+}n network can be electronically modified by adjusting the interaction of the apical linkers interconnecting the layers, which has strong implications for the magnetic properties. It is then demonstrated that the degree of covalent character of the apical interaction explains the difference in magnetic exchange between the two species. We have also investigated the mechanical deformation of the network induced by nonhydrostatic compression that affects the structure depending on the crystal orientation. The obtained results suggest the existence of "Jahn-Teller frustration" triggered at the highest hydrostatic pressure limit.
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Affiliation(s)
- Rebecca Scatena
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Fabio Montisci
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Arianna Lanza
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Nicola P M Casati
- Paul Scherrer Institute, Laboratory for Synchrotron Radiation Condensed Matter, Forschungsstrasse 111, 5232 Villigen, Switzerland
| | - Piero Macchi
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.,Department of Chemistry, Materials and Chemical Engineering, Polytechnic of Milan, via Mancinelli 7, 20131 Milan, Italy
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25
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Lee WY, Park NW, Kang MS, Kim GS, Jang HW, Saitoh E, Lee SK. Surface Coverage Dependence of Spin-to-Charge Current across Pt/MoS 2/Y 3Fe 5O 12 Layers via Longitudinal Spin Seebeck Effect. J Phys Chem Lett 2020; 11:5338-5344. [PMID: 32558573 DOI: 10.1021/acs.jpclett.0c01502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The voltage induced by the inverse spin Hall effect (ISHE) is affected by several factors, including the spin Hall angle of the normal metal (NM), the quality and magnetic properties of the ferromagnetic material (FM), and the interface conditions between the NM and FM bilayers in longitudinal spin Seebeck effect (LSSE) measurement. Specifically, the interface conditions in NM/FM systems via LSSE devices play a crucial role in determining the efficiency of spin current injection into the NM layer. In this letter, we report a new approach to controlling the efficiency of spin current injection into a Pt layer across a Pt/Y3Fe5O12 (YIG) interface by surface coverage of the intermediate layer. A continuous, large-area multilayer molybdenum dichalcogenide (MoS2) thin film grown by chemical vapor deposition is inserted between the Pt and YIG layers in the LSSE configuration. We found that, when the large-area multilayer MoS2 film was present, the measured ISHE-induced voltage and theoretically calculated spin current in the Pt/MoS2/YIG trilayer increased by ∼510% and 470%, respectively, compared to those of a Pt/YIG bilayer. The induced voltage and spin current were very sensitive to the surface conductance, which was affected by the surface coverage of the multilayer MoS2 films in the LSSE measurement. Furthermore, the theoretically calculated spin current and spin mixing conductance in the trilayer geometry are in qualitatively good agreement with the experimental observations. These measurements enable us to explain the effect of the interface conditions on the spin Seebeck effect in spin transport.
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Affiliation(s)
- Won-Yong Lee
- Department of Physics, Chung-Ang University, Seoul 06974, Republic of Korea
| | - No-Won Park
- Department of Physics, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Min-Sung Kang
- Department of Physics, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Gil-Sung Kim
- Department of Physics, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Ho Won Jang
- Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Eiji Saitoh
- WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
| | - Sang-Kwon Lee
- Department of Physics, Chung-Ang University, Seoul 06974, Republic of Korea
- WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
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26
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Han J, Zhang P, Bi Z, Fan Y, Safi TS, Xiang J, Finley J, Fu L, Cheng R, Liu L. Birefringence-like spin transport via linearly polarized antiferromagnetic magnons. NATURE NANOTECHNOLOGY 2020; 15:563-568. [PMID: 32483320 DOI: 10.1038/s41565-020-0703-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/29/2020] [Indexed: 05/12/2023]
Abstract
Antiferromagnets (AFMs) possess great potential in spintronics because of their immunity to external magnetic disturbance, the absence of a stray field or the resonance in the terahertz range1,2. The coupling of insulating AFMs to spin-orbit materials3-7 enables spin transport via AFM magnons. In particular, spin transmission over several micrometres occurs in some AFMs with easy-axis anisotropy8,9. Easy-plane AFMs with two orthogonal, linearly polarized magnon eigenmodes own unique advantages for low-energy control of ultrafast magnetic dynamics2. However, it is commonly conceived that these magnon modes are less likely to transmit spins because of their vanishing angular momentum9-11. Here we report experimental evidence that an easy-plane insulating AFM, an α-Fe2O3 thin film, can efficiently transmit spins over micrometre distances. The spin decay length shows an unconventional temperature dependence that cannot be captured considering solely thermal magnon scatterings. We interpret our observations in terms of an interference of two linearly polarized, propagating magnons in analogy to the birefringence effect in optics. Furthermore, our devices can realize a bi-stable spin-current switch with a 100% on/off ratio under zero remnant magnetic field. These findings provide additional tools for non-volatile, low-field control of spin transport in AFM systems.
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Affiliation(s)
- Jiahao Han
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Pengxiang Zhang
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Zhen Bi
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yabin Fan
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Taqiyyah S Safi
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Junxiang Xiang
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Joseph Finley
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ran Cheng
- Department of Electrical and Computer Engineering, University of California, Riverside, CA, USA
| | - Luqiao Liu
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
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27
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Dąbrowski M, Nakano T, Burn DM, Frisk A, Newman DG, Klewe C, Li Q, Yang M, Shafer P, Arenholz E, Hesjedal T, van der Laan G, Qiu ZQ, Hicken RJ. Coherent Transfer of Spin Angular Momentum by Evanescent Spin Waves within Antiferromagnetic NiO. PHYSICAL REVIEW LETTERS 2020; 124:217201. [PMID: 32530697 DOI: 10.1103/physrevlett.124.217201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
Insulating antiferromagnets have recently emerged as efficient and robust conductors of spin current. Element-specific and phase-resolved x-ray ferromagnetic resonance has been used to probe the injection and transmission of ac spin current through thin epitaxial NiO(001) layers. The spin current is found to be mediated by coherent evanescent spin waves of GHz frequency, rather than propagating magnons of THz frequency, paving the way towards coherent control of the phase and amplitude of spin currents within an antiferromagnetic insulator at room temperature.
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Affiliation(s)
- Maciej Dąbrowski
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, Devon EX4 4QL, United Kingdom
| | - Takafumi Nakano
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, Devon EX4 4QL, United Kingdom
- Spintronics Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568, Japan
| | - David M Burn
- Magnetic Spectroscopy Group, Diamond Light Source, Didcot OX11 0DE, United Kingdom
| | - Andreas Frisk
- Magnetic Spectroscopy Group, Diamond Light Source, Didcot OX11 0DE, United Kingdom
| | - David G Newman
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, Devon EX4 4QL, United Kingdom
| | - Christoph Klewe
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Qian Li
- Department of Physics, University of California at Berkeley, California 94720, USA
| | - Mengmeng Yang
- Department of Physics, University of California at Berkeley, California 94720, USA
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Elke Arenholz
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Thorsten Hesjedal
- Department of Physics, Clarendon Laboratory, University of Oxford, OX1 Oxford 3PU, United Kingdom
| | - Gerrit van der Laan
- Magnetic Spectroscopy Group, Diamond Light Source, Didcot OX11 0DE, United Kingdom
| | - Zi Q Qiu
- Department of Physics, University of California at Berkeley, California 94720, USA
| | - Robert J Hicken
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, Devon EX4 4QL, United Kingdom
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28
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Fabrication of Au/Ni/NiO heterostructure nanowires by electrochemical deposition and their temperature dependent magnetic properties. J SOLID STATE CHEM 2020. [DOI: 10.1016/j.jssc.2020.121186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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29
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Wang Y, Zhu D, Yang Y, Lee K, Mishra R, Go G, Oh SH, Kim DH, Cai K, Liu E, Pollard SD, Shi S, Lee J, Teo KL, Wu Y, Lee KJ, Yang H. Magnetization switching by magnon-mediated spin torque through an antiferromagnetic insulator. Science 2019; 366:1125-1128. [DOI: 10.1126/science.aav8076] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 08/21/2019] [Accepted: 11/04/2019] [Indexed: 12/15/2022]
Abstract
Widespread applications of magnetic devices require an efficient means to manipulate the local magnetization. One mechanism is the electrical spin-transfer torque associated with electron-mediated spin currents; however, this suffers from substantial energy dissipation caused by Joule heating. We experimentally demonstrated an alternative approach based on magnon currents and achieved magnon-torque–induced magnetization switching in Bi2Se3/antiferromagnetic insulator NiO/ferromagnet devices at room temperature. The magnon currents carry spin angular momentum efficiently without involving moving electrons through a 25-nanometer-thick NiO layer. The magnon torque is sufficient to control the magnetization, which is comparable with previously observed electrical spin torque ratios. This research, which is relevant to the energy-efficient control of spintronic devices, will invigorate magnon-based memory and logic devices.
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Affiliation(s)
- Yi Wang
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), Dalian University of Technology, Dalian 116024, China
| | - Dapeng Zhu
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Yumeng Yang
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Kyusup Lee
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Rahul Mishra
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Gyungchoon Go
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Korea
| | - Se-Hyeok Oh
- Department of Nano-Semiconductor and Engineering, Korea University, Seoul 02841, Korea
| | - Dong-Hyun Kim
- Department of Semiconductor Systems Engineering, Korea University, Seoul 02841, Korea
| | - Kaiming Cai
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Enlong Liu
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Shawn D. Pollard
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Shuyuan Shi
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Jongmin Lee
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Kie Leong Teo
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Yihong Wu
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
| | - Kyung-Jin Lee
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Korea
- Department of Nano-Semiconductor and Engineering, Korea University, Seoul 02841, Korea
- Department of Semiconductor Systems Engineering, Korea University, Seoul 02841, Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore
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30
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Coherent ac spin current transmission across an antiferromagnetic CoO insulator. Nat Commun 2019; 10:5265. [PMID: 31748514 PMCID: PMC6868243 DOI: 10.1038/s41467-019-13280-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 10/24/2019] [Indexed: 11/15/2022] Open
Abstract
The recent discovery of spin current transmission through antiferromagnetic insulating materials opens up vast opportunities for fundamental physics and spintronics applications. The question currently surrounding this topic is: whether and how could THz antiferromagnetic magnons mediate a GHz spin current? This mismatch of frequencies becomes particularly critical for the case of coherent ac spin current, raising the fundamental question of whether a GHz ac spin current can ever keep its coherence inside an antiferromagnetic insulator and so drive the spin precession of another ferromagnet layer coherently? Utilizing element- and time-resolved x-ray pump-probe measurements on Py/Ag/CoO/Ag/Fe75Co25/MgO(001) heterostructures, here we demonstrate that a coherent GHz ac spin current pumped by the Py ferromagnetic resonance can transmit coherently across an antiferromagnetic CoO insulating layer to drive a coherent spin precession of the Fe75Co25 layer. Further measurement results favor thermal magnons rather than evanescent spin waves as the mediator of the coherent ac spin current in CoO. The mechanism underpinning the frequency mismatch between THz magnons and the GHz spin currents observed in antiferromagnetic insulators remains unknown. Here, the authors demonstrate that, in a Py/Ag/CoO/Ag/Fe75Co25/MgO(001) heterostructure, a GHz spin current transmits coherently across the antiferromagnetic CoO insulating layer to drive a coherent spin precession of the ferromagnetic Fe75Co25 layer.
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31
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Li J, Shi Z, Ortiz VH, Aldosary M, Chen C, Aji V, Wei P, Shi J. Spin Seebeck Effect from Antiferromagnetic Magnons and Critical Spin Fluctuations in Epitaxial FeF_{2} Films. PHYSICAL REVIEW LETTERS 2019; 122:217204. [PMID: 31283322 DOI: 10.1103/physrevlett.122.217204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Indexed: 06/09/2023]
Abstract
We report a longitudinal spin Seebeck effect (SSE) study in epitaxially grown FeF_{2}(110) antiferromagnetic (AFM) thin films with strong uniaxial anisotropy over the temperature range of 3.8-250 K. Both the magnetic-field and temperature-dependent SSE signals below the Néel temperature (T_{N}=70 K) of the FeF_{2} films are consistent with a theoretical model based on the excitations of AFM magnons without any net induced static magnetic moment. In addition to the characteristic low-temperature SSE peak associated with the AFM magnons, there is another SSE peak at T_{N} which extends well into the paramagnetic phase. All the SSE data taken at different magnetic fields up to 12 T near and above the critical point T_{N} follow the critical scaling law very well with the critical exponents for magnetic susceptibility of 3D Ising systems, which suggests that the AFM spin correlation is responsible for the observed SSE near T_{N}.
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Affiliation(s)
- Junxue Li
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - Zhong Shi
- School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Victor H Ortiz
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - Mohammed Aldosary
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
- Department of Physics and Astronomy, King Saud University, Riyadh 11451, Saudi Arabia
| | - Cliff Chen
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - Vivek Aji
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - Peng Wei
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - Jing Shi
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
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32
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Wu R, Yun C, Wang X, Lu P, Li W, Lin Y, Choi EM, Wang H, MacManus-Driscoll JL. All-Oxide Nanocomposites to Yield Large, Tunable Perpendicular Exchange Bias above Room Temperature. ACS APPLIED MATERIALS & INTERFACES 2018; 10:42593-42602. [PMID: 30394088 DOI: 10.1021/acsami.8b14635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In all-oxide-based spintronic devices, large exchange bias effect with robustness against temperature fluctuation and compatibility with perpendicular magnetic recording is highly desired. In this work, rock-salt antiferromagnetic NiO with a Néel temperature ( TN) of ∼525 K and spinel ferrimagnetic NiFe2O4 with a high Curie temperature, TC, ≈ 790 K and TC > TN were chosen as compatible materials to form a well-phase-separated, vertically aligned nanocomposite thin film. In this nanoengineered thin film, an exchange bias effect with a blocking temperature far above room temperature has been achieved. A large perpendicular exchange bias field of up to 0.91 kOe with an interfacial exchange energy density of 0.11-0.34 erg/cm2 was obtained at room temperature. It was also demonstrated that the exchange bias effect can be easily tuned by changing the alignment of the magnetic moments in the NiO phase using substrates of different crystalline orientations and by changing the microstructure of the film with substrates of different lattice parameters. The results demonstrate that proper choice of the phases (including use of nonperovskite compositions) and careful strain engineering and nanostructure engineering makes oxide nanocomposites strong potential candidate systems for next generation spintronic devices.
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Affiliation(s)
- Rui Wu
- Department of Materials Science & Metallurgy , University of Cambridge , Cambridge CB3 0FS , U.K
| | - Chao Yun
- Department of Materials Science & Metallurgy , University of Cambridge , Cambridge CB3 0FS , U.K
| | - Xuejing Wang
- Materials Engineering , Purdue University , West Lafayette , Indiana 47907 , United States
| | - Ping Lu
- Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| | - Weiwei Li
- Department of Materials Science & Metallurgy , University of Cambridge , Cambridge CB3 0FS , U.K
| | - Yisong Lin
- Department of Materials Science & Metallurgy , University of Cambridge , Cambridge CB3 0FS , U.K
| | - Eun-Mi Choi
- Department of Materials Science & Metallurgy , University of Cambridge , Cambridge CB3 0FS , U.K
| | - Haiyan Wang
- Materials Engineering , Purdue University , West Lafayette , Indiana 47907 , United States
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33
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Paramagnon-Enhanced Spin Currents in a Lattice near the Curie Point. Sci Rep 2018; 8:17108. [PMID: 30459345 PMCID: PMC6244084 DOI: 10.1038/s41598-018-35336-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 10/29/2018] [Indexed: 11/08/2022] Open
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34
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Moriyama T, Oda K, Ohkochi T, Kimata M, Ono T. Spin torque control of antiferromagnetic moments in NiO. Sci Rep 2018; 8:14167. [PMID: 30242184 PMCID: PMC6155024 DOI: 10.1038/s41598-018-32508-w] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/03/2018] [Indexed: 11/30/2022] Open
Abstract
For a long time, there were no efficient ways of controlling antiferromagnets. Quite a strong magnetic field was required to manipulate the magnetic moments because of a high molecular field and a small magnetic susceptibility. It was also difficult to detect the orientation of the magnetic moments since the net magnetic moment is effectively zero. For these reasons, research on antiferromagnets has not been progressed as drastically as that on ferromagnets which are the main materials in modern spintronic devices. Here we show that the magnetic moments in NiO, a typical natural antiferromagnet, can indeed be controlled by the spin torque with a relatively small electric current density (~4 × 107 A/cm2) and their orientation is detected by the transverse resistance resulting from the spin Hall magnetoresistance. The demonstrated techniques of controlling and detecting antiferromagnets would outstandingly promote the methodologies in the recently emerged “antiferromagnetic spintronics”. Furthermore, our results essentially lead to a spin torque antiferromagnetic memory.
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Affiliation(s)
- Takahiro Moriyama
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan. .,Center for Spintronics Research Network, Osaka University, Toyonaka, Osaka, 560-8531, Japan.
| | - Kent Oda
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Takuo Ohkochi
- Japan Synchrotron Radiation Research Institute, Sayo, Hyogo, 679-5198, Japan
| | - Motoi Kimata
- Institute for Materials Research, Tohoku University, Sendai, Miyagi, 980-8577, Japan
| | - Teruo Ono
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan.,Center for Spintronics Research Network, Osaka University, Toyonaka, Osaka, 560-8531, Japan
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35
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Lebrun R, Ross A, Bender SA, Qaiumzadeh A, Baldrati L, Cramer J, Brataas A, Duine RA, Kläui M. Tunable long-distance spin transport in a crystalline antiferromagnetic iron oxide. Nature 2018; 561:222-225. [PMID: 30209370 PMCID: PMC6485392 DOI: 10.1038/s41586-018-0490-7] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/25/2018] [Indexed: 11/20/2022]
Abstract
Spintronics relies on the transport of spins, the intrinsic angular momentum of electrons, as an alternative to the transport of electron charge as in conventional electronics. The long-term goal of spintronics research is to develop spin-based, low-dissipation computing-technology devices. Recently, long-distance transport of a spin current was demonstrated across ferromagnetic insulators1. However, antiferromagnetically ordered materials, the most common class of magnetic materials, have several crucial advantages over ferromagnetic systems for spintronics applications2: antiferromagnets have no net magnetic moment, making them stable and impervious to external fields, and can be operated at terahertz-scale frequencies3. Although the properties of antiferromagnets are desirable for spin transport4-7, indirect observations of such transport indicate that spin transmission through antiferromagnets is limited to only a few nanometres8-10. Here we demonstrate long-distance propagation of spin currents through a single crystal of the antiferromagnetic insulator haematite (α-Fe2O3)11, the most common antiferromagnetic iron oxide, by exploiting the spin Hall effect for spin injection. We control the flow of spin current across a haematite-platinum interface-at which spins accumulate, generating the spin current-by tuning the antiferromagnetic resonance frequency using an external magnetic field12. We find that this simple antiferromagnetic insulator conveys spin information parallel to the antiferromagnetic Néel order over distances of more than tens of micrometres. This mechanism transports spins as efficiently as the most promising complex ferromagnets1. Our results pave the way to electrically tunable, ultrafast, low-power, antiferromagnetic-insulator-based spin-logic devices6,13 that operate without magnetic fields at room temperature.
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Affiliation(s)
- R Lebrun
- Institute for Physics, Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - A Ross
- Institute for Physics, Johannes Gutenberg-University Mainz, Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, Mainz, Germany
| | - S A Bender
- Utrecht University, Utrecht, The Netherlands
| | - A Qaiumzadeh
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway
| | - L Baldrati
- Institute for Physics, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - J Cramer
- Institute for Physics, Johannes Gutenberg-University Mainz, Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, Mainz, Germany
| | - A Brataas
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway
| | - R A Duine
- Utrecht University, Utrecht, The Netherlands
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - M Kläui
- Institute for Physics, Johannes Gutenberg-University Mainz, Mainz, Germany.
- Graduate School of Excellence Materials Science in Mainz, Mainz, Germany.
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway.
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36
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Jhajhria D, Pandya DK, Chaudhary S. Influence of the thickness of an antiferromagnetic IrMn layer on the static and dynamic magnetization of weakly coupled CoFeB/IrMn/CoFeB trilayers. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:2198-2208. [PMID: 30202690 PMCID: PMC6122295 DOI: 10.3762/bjnano.9.206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 08/03/2018] [Indexed: 06/08/2023]
Abstract
The static and dynamic magnetization response of the CoFeB/IrMn/CoFeB trilayer system with varying thickness of the antiferromagnetic (AF) IrMn layer is investigated using magnetization hysteresis (M-H) and ferromagnetic resonance (FMR) measurements. The study shows that the two CoFeB layers are coupled via a long-range dynamic exchange effect through the IrMn layer up to a thickness of 6 nm. It is found that with the increase in IrMn layer thickness a nearly linear enhancement of the effective magnetic damping constant occurs, which is associated with the simultaneous influence of spin pumping and interlayer exchange coupling effects. An extrinsic contribution to the linewidth originating from the two-magnon scattering is also discussed. The AF-induced interfacial damping parameter is derived by studying the evolution of damping with inverse CoFeB thickness. The static magnetic measurements also reveal the interlayer exchange coupling across the IrMn layer both at room temperature and low temperature. The asymmetric hysteresis loop and training effect observed at low temperature is related to the presence of a metastable AF domain state. We show that both the static and dynamic magnetic properties of trilayer films can be adjusted over a wide range by changing the thickness of the IrMn spacer layer.
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Affiliation(s)
- Deepika Jhajhria
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Dinesh K Pandya
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Sujeet Chaudhary
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
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37
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Cramer J, Fuhrmann F, Ritzmann U, Gall V, Niizeki T, Ramos R, Qiu Z, Hou D, Kikkawa T, Sinova J, Nowak U, Saitoh E, Kläui M. Magnon detection using a ferroic collinear multilayer spin valve. Nat Commun 2018. [PMID: 29540718 PMCID: PMC5852167 DOI: 10.1038/s41467-018-03485-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Information transport and processing by pure magnonic spin currents in insulators is a promising alternative to conventional charge-current-driven spintronic devices. The absence of Joule heating and reduced spin wave damping in insulating ferromagnets have been suggested for implementing efficient logic devices. After the successful demonstration of a majority gate based on the superposition of spin waves, further components are required to perform complex logic operations. Here, we report on magnetization orientation-dependent spin current detection signals in collinear magnetic multilayers inspired by the functionality of a conventional spin valve. In Y3Fe5O12|CoO|Co, we find that the detection amplitude of spin currents emitted by ferromagnetic resonance spin pumping depends on the relative alignment of the Y3Fe5O12 and Co magnetization. This yields a spin valve-like behavior with an amplitude change of 120% in our systems. We demonstrate the reliability of the effect and identify its origin by both temperature-dependent and power-dependent measurements.
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Affiliation(s)
- Joel Cramer
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany.,Graduate School of Excellence Materials Science in Mainz, 55128, Mainz, Germany
| | - Felix Fuhrmann
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Ulrike Ritzmann
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany.,Department of Physics, University of Konstanz, 78457, Konstanz, Germany
| | - Vanessa Gall
- Department of Physics, University of Konstanz, 78457, Konstanz, Germany
| | - Tomohiko Niizeki
- Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - Rafael Ramos
- Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - Zhiyong Qiu
- Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.,School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024, China
| | - Dazhi Hou
- Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - Takashi Kikkawa
- Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.,Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
| | - Jairo Sinova
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Ulrich Nowak
- Department of Physics, University of Konstanz, 78457, Konstanz, Germany
| | - Eiji Saitoh
- Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.,Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan.,Center for Spintronics Research Network, Tohoku University, Sendai, 980-8577, Japan.,Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, 319-1195, Japan
| | - Mathias Kläui
- Institute of Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany. .,Graduate School of Excellence Materials Science in Mainz, 55128, Mainz, Germany.
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38
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Moriyama T, Kamiya M, Oda K, Tanaka K, Kim KJ, Ono T. Magnetic Moment Orientation-Dependent Spin Dissipation in Antiferromagnets. PHYSICAL REVIEW LETTERS 2017; 119:267204. [PMID: 29328700 DOI: 10.1103/physrevlett.119.267204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Indexed: 06/07/2023]
Abstract
Spin interaction in antiferromagnetic materials is of central interest in the recently emerging antiferromagnetic spintronics. In this Letter, we explore the spin current interaction in antiferromagnetic FeMn by the spin pumping effect. Exchange biased FeNi/FeMn films, in which the Néel vector can be presumably controlled via the exchange spring effect, are employed to investigate the damping enhancement depending on the relative orientation between the Néel vector and the polarization of the pumped spin current. The correlation between the enhanced damping and the strength of the exchange bias suggests that the twisting of the Néel vector induces an additional spin dissipation, which verifies that the Slonczewski-type spin torque is effective even in antiferromagnetic materials.
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Affiliation(s)
- Takahiro Moriyama
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Michinari Kamiya
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Kent Oda
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Kensho Tanaka
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Kab-Jin Kim
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Teruo Ono
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
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39
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Gandhi AC, Chan TS, Pant J, Wu SY. Strong Pinned-Spin-Mediated Memory Effect in NiO Nanoparticles. NANOSCALE RESEARCH LETTERS 2017; 12:207. [PMID: 28325039 PMCID: PMC5359196 DOI: 10.1186/s11671-017-1988-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/09/2017] [Indexed: 06/06/2023]
Abstract
After a decade of effort, a large number of magnetic memory nanoparticles with different sizes and core/shell compositions have been developed. While the field-cooling memory effect is often attributed to particle size and distribution effects, other magnetic coupling parameters such as inter- and intra-coupling strength, exchange bias, interfacial pinned spins, and the crystallinity of the nanoparticles also have a significant influence on magnetization properties and mechanisms. In this study, we used the analysis of static- and dynamic-magnetization measurements to investigate NiO nanoparticles with different sizes and discussed how these field-cooling strengths affect their memory properties. We conclude that the observed field-cooling memory effect from bare, small size NiO nanoparticles arises because of the unidirectional anisotropy which is mediated by the interfacial strongly pinned spins.
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Affiliation(s)
- Ashish Chhaganlal Gandhi
- Department of Physics, National Dong Hwa University, Hualien, 97401, Taiwan
- Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan
| | - Ting Shan Chan
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Jayashree Pant
- Department of Physics, Abasaheb Garware College, Savitribai Phule Pune University, Pune, India
| | - Sheng Yun Wu
- Department of Physics, National Dong Hwa University, Hualien, 97401, Taiwan.
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40
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Lee AJ, Brangham JT, Cheng Y, White SP, Ruane WT, Esser BD, McComb DW, Hammel PC, Yang F. Metallic ferromagnetic films with magnetic damping under 1.4 × 10 -3. Nat Commun 2017; 8:234. [PMID: 28794430 PMCID: PMC5550470 DOI: 10.1038/s41467-017-00332-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/21/2017] [Indexed: 11/14/2022] Open
Abstract
Low-damping magnetic materials have been widely used in microwave and spintronic applications because of their low energy loss and high sensitivity. While the Gilbert damping constant can reach 10−4 to 10−5 in some insulating ferromagnets, metallic ferromagnets generally have larger damping due to magnon scattering by conduction electrons. Meanwhile, low-damping metallic ferromagnets are desired for charge-based spintronic devices. Here, we report the growth of Co25Fe75 epitaxial films with excellent crystalline quality evident by the clear Laue oscillations and exceptionally narrow rocking curve in the X-ray diffraction scans as well as from scanning transmission electron microscopy. Remarkably, the Co25Fe75 epitaxial films exhibit a damping constant <1.4 × 10−3, which is comparable to the values for some high-quality Y3Fe5O12 films. This record low damping for metallic ferromagnets offers new opportunities for charge-based applications such as spin-transfer-torque-induced switching and magnetic oscillations. Owing to their conductivity, low-damping metallic ferromagnets are preferred to insulating ferromagnets in charge-based spintronic devices, but are not yet well developed. Here the authors achieve low magnetic damping in CoFe epitaxial films which is comparable to conventional insulating ferromagnetic YIG films.
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Affiliation(s)
- Aidan J Lee
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
| | - Jack T Brangham
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
| | - Yang Cheng
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
| | - Shane P White
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
| | - William T Ruane
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
| | - Bryan D Esser
- Center for Electron Microscopy and Analysis, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - David W McComb
- Center for Electron Microscopy and Analysis, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - P Chris Hammel
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA
| | - Fengyuan Yang
- Department of Physics, The Ohio State University, Columbus, OH, 43210, USA.
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41
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Bender SA, Skarsvåg H, Brataas A, Duine RA. Enhanced Spin Conductance of a Thin-Film Insulating Antiferromagnet. PHYSICAL REVIEW LETTERS 2017; 119:056804. [PMID: 28949746 DOI: 10.1103/physrevlett.119.056804] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Indexed: 06/07/2023]
Abstract
We investigate spin transport by thermally excited spin waves in an antiferromagnetic insulator. Starting from a stochastic Landau-Lifshitz-Gilbert phenomenology, we obtain the out-of-equilibrium spin-wave properties. In linear response to spin biasing and a temperature gradient, we compute the spin transport through a normal-metal-antiferromagnet-normal-metal heterostructure. We show that the spin conductance diverges as one approaches the spin-flop transition; this enhancement of the conductance should be readily observable by sweeping the magnetic field across the spin-flop transition. The results from such experiments may, on the one hand, enhance our understanding of spin transport near a phase transition, and on the other be useful for applications that require a large degree of tunability of spin currents. In contrast, the spin Seebeck coefficient does not diverge at the spin-flop transition. Furthermore, the spin Seebeck coefficient is finite even at zero magnetic field, provided that the normal metal contacts break the symmetry between the antiferromagnetic sublattices.
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Affiliation(s)
- Scott A Bender
- Utrecht University, Princetonplein 5, 3584 CC Utrecht, Netherlands
| | - Hans Skarsvåg
- Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Arne Brataas
- Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Rembert A Duine
- Utrecht University, Princetonplein 5, 3584 CC Utrecht, Netherlands
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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42
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Ma X, Yu G, Razavi SA, Sasaki SS, Li X, Hao K, Tolbert SH, Wang KL, Li X. Dzyaloshinskii-Moriya Interaction across an Antiferromagnet-Ferromagnet Interface. PHYSICAL REVIEW LETTERS 2017; 119:027202. [PMID: 28753324 DOI: 10.1103/physrevlett.119.027202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Indexed: 06/07/2023]
Abstract
The antiferromagnet- (AFM-)ferromagnet (FM) interfaces are of central importance in recently developed pure electric or ultrafast control of FM spins, where the underlying mechanisms remain unresolved. Here we report the direct observation of an Dzyaloshinskii-Moriya interaction (DMI) across the AFM-FM interface of IrMn/CoFeB thin films. The interfacial DMI is quantitatively measured from the asymmetric spin-wave dispersion in the FM layer using Brillouin light scattering. The DMI strength is enhanced by a factor of 7 with increasing IrMn layer thickness in the range of 1-7.5 nm. Our findings provide deeper insight into the coupling at the AFM-FM interface and may stimulate new device concepts utilizing chiral spin textures such as magnetic Skyrmions in AFM-FM heterostructures.
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Affiliation(s)
- Xin Ma
- Department of Physics, Center for Quantum systems, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Guoqiang Yu
- Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA
| | - Seyed A Razavi
- Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA
| | - Stephen S Sasaki
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | - Xiang Li
- Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA
| | - Kai Hao
- Department of Physics, Center for Quantum systems, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Sarah H Tolbert
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
- Department of Materials Science and Engineering, University of California, Los Angeles, California 90095, USA
| | - Kang L Wang
- Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA
- Department of Physics, University of California, Los Angeles, California 90095, USA
| | - Xiaoqin Li
- Department of Physics, Center for Quantum systems, The University of Texas at Austin, Austin, Texas 78712, USA
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43
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Hou D, Qiu Z, Barker J, Sato K, Yamamoto K, Vélez S, Gomez-Perez JM, Hueso LE, Casanova F, Saitoh E. Tunable Sign Change of Spin Hall Magnetoresistance in Pt/NiO/YIG Structures. PHYSICAL REVIEW LETTERS 2017; 118:147202. [PMID: 28430518 DOI: 10.1103/physrevlett.118.147202] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Indexed: 06/07/2023]
Abstract
Spin Hall magnetoresistance (SMR) has been investigated in Pt/NiO/YIG structures in a wide range of temperature and NiO thickness. The SMR shows a negative sign below a temperature that increases with the NiO thickness. This is contrary to a conventional SMR theory picture applied to the Pt/YIG bilayer, which always predicts a positive SMR. The negative SMR is found to persist even when NiO blocks the spin transmission between Pt and YIG, indicating it is governed by the spin current response of the NiO layer. We explain the negative SMR by the NiO "spin flop" coupled with YIG, which can be overridden at higher temperature by positive SMR contribution from YIG. This highlights the role of magnetic structure in antiferromagnets for transport of pure spin current in multilayers.
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Affiliation(s)
- Dazhi Hou
- WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577, Japan
| | - Zhiyong Qiu
- WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577, Japan
| | - Joseph Barker
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Koji Sato
- WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Kei Yamamoto
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55128 Mainz, Germany
- Department of Physics, Kobe University, 1-1 Rokkodai, Kobe 657-8501, Japan
| | - Saül Vélez
- CIC nanoGUNE, 20018 Donostia-San Sebastian, Basque Country, Spain
| | | | - Luis E Hueso
- CIC nanoGUNE, 20018 Donostia-San Sebastian, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Basque Country, Spain
| | - Fèlix Casanova
- CIC nanoGUNE, 20018 Donostia-San Sebastian, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Basque Country, Spain
| | - Eiji Saitoh
- WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577, Japan
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan
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44
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Hellman F, Hoffmann A, Tserkovnyak Y, Beach GSD, Fullerton EE, Leighton C, MacDonald AH, Ralph DC, Arena DA, Dürr HA, Fischer P, Grollier J, Heremans JP, Jungwirth T, Kimel AV, Koopmans B, Krivorotov IN, May SJ, Petford-Long AK, Rondinelli JM, Samarth N, Schuller IK, Slavin AN, Stiles MD, Tchernyshyov O, Thiaville A, Zink BL. Interface-Induced Phenomena in Magnetism. REVIEWS OF MODERN PHYSICS 2017; 89:025006. [PMID: 28890576 PMCID: PMC5587142 DOI: 10.1103/revmodphys.89.025006] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
This article reviews static and dynamic interfacial effects in magnetism, focusing on interfacially-driven magnetic effects and phenomena associated with spin-orbit coupling and intrinsic symmetry breaking at interfaces. It provides a historical background and literature survey, but focuses on recent progress, identifying the most exciting new scientific results and pointing to promising future research directions. It starts with an introduction and overview of how basic magnetic properties are affected by interfaces, then turns to a discussion of charge and spin transport through and near interfaces and how these can be used to control the properties of the magnetic layer. Important concepts include spin accumulation, spin currents, spin transfer torque, and spin pumping. An overview is provided to the current state of knowledge and existing review literature on interfacial effects such as exchange bias, exchange spring magnets, spin Hall effect, oxide heterostructures, and topological insulators. The article highlights recent discoveries of interface-induced magnetism and non-collinear spin textures, non-linear dynamics including spin torque transfer and magnetization reversal induced by interfaces, and interfacial effects in ultrafast magnetization processes.
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Affiliation(s)
- Frances Hellman
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Axel Hoffmann
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Yaroslav Tserkovnyak
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Geoffrey S D Beach
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Eric E Fullerton
- Center for Memory and Recording Research, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0401, USA
| | - Chris Leighton
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Allan H MacDonald
- Department of Physics, University of Texas at Austin, Austin, Texas 78712-0264, USA
| | - Daniel C Ralph
- Physics Department, Cornell University, Ithaca, New York 14853, USA; Kavli Institute at Cornell, Cornell University, Ithaca, New York 14853, USA
| | - Dario A Arena
- Department of Physics, University of South Florida, Tampa, Florida 33620-7100, USA
| | - Hermann A Dürr
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Peter Fischer
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; Physics Department, University of California, 1156 High Street, Santa Cruz, California 94056, USA
| | - Julie Grollier
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - Joseph P Heremans
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210, USA; Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210, USA; Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Tomas Jungwirth
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53 Praha 6, Czech Republic; School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Alexey V Kimel
- Radboud University, Institute for Molecules and Materials, Nijmegen 6525 AJ, The Netherlands
| | - Bert Koopmans
- Department of Applied Physics, Center for NanoMaterials, COBRA Research Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Ilya N Krivorotov
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
| | - Steven J May
- Department of Materials Science & Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA
| | - Amanda K Petford-Long
- Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, USA
| | - James M Rondinelli
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Nitin Samarth
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Ivan K Schuller
- Department of Physics and Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA; Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Andrei N Slavin
- Department of Physics, Oakland University, Rochester, Michigan 48309, USA
| | - Mark D Stiles
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6202, USA
| | - Oleg Tchernyshyov
- Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - André Thiaville
- Laboratoire de Physique des Solides, UMR CNRS 8502, Université Paris-Sud, 91405 Orsay, France
| | - Barry L Zink
- Department of Physics and Astronomy, University of Denver, Denver, CO 80208, USA
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45
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Qaiumzadeh A, Skarsvåg H, Holmqvist C, Brataas A. Spin Superfluidity in Biaxial Antiferromagnetic Insulators. PHYSICAL REVIEW LETTERS 2017; 118:137201. [PMID: 28409991 DOI: 10.1103/physrevlett.118.137201] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Indexed: 06/07/2023]
Abstract
Antiferromagnets may exhibit spin superfluidity since the dipole interaction is weak. We seek to establish that this phenomenon occurs in insulators such as NiO, which is a good spin conductor according to previous studies. We investigate nonlocal spin transport in a planar antiferromagnetic insulator with a weak uniaxial anisotropy. The anisotropy hinders spin superfluidity by creating a substantial threshold that the current must overcome. Nevertheless, we show that applying a high magnetic field removes this obstacle near the spin-flop transition of the antiferromagnet. Importantly, the spin superfluidity can then persist across many micrometers, even in dirty samples.
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Affiliation(s)
- Alireza Qaiumzadeh
- Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Hans Skarsvåg
- Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Cecilia Holmqvist
- Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Arne Brataas
- Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
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46
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Lin W, Chien CL. Electrical Detection of Spin Backflow from an Antiferromagnetic Insulator/Y_{3}Fe_{5}O_{12} Interface. PHYSICAL REVIEW LETTERS 2017; 118:067202. [PMID: 28234519 DOI: 10.1103/physrevlett.118.067202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Indexed: 06/06/2023]
Abstract
Spin Hall magnetoresistance (SMR) has been observed in Pt/NiO/Y_{3}Fe_{5}O_{12} (YIG) heterostructures with characteristics very different from those in Pt/YIG. This phenomenon indicates that a spin current generated by the spin Hall effect in Pt transmits through the insulating NiO and is reflected from the NiO/YIG interface. The SMR in Pt/NiO/YIG shows a strong temperature dependence dominated by effective spin conductance, due to antiferromagnetic magnons and spin fluctuation. Inverted SMR has been observed below a temperature which increases with the NiO thickness, suggesting a spin-flip reflection from the antiferromagnetic NiO exchange coupled with the YIG.
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Affiliation(s)
- Weiwei Lin
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - C L Chien
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
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47
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Boona SR, Vandaele K, Boona IN, McComb DW, Heremans JP. Observation of spin Seebeck contribution to the transverse thermopower in Ni-Pt and MnBi-Au bulk nanocomposites. Nat Commun 2016; 7:13714. [PMID: 27941927 PMCID: PMC5159888 DOI: 10.1038/ncomms13714] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 10/25/2016] [Indexed: 12/02/2022] Open
Abstract
Transverse thermoelectric devices produce electric fields perpendicular to an incident heat flux. Classically, this process is driven by the Nernst effect in bulk solids, wherein a magnetic field generates a Lorentz force on thermally excited electrons. The spin Seebeck effect also produces magnetization-dependent transverse electric fields. It is traditionally observed in thin metallic films deposited on electrically insulating ferromagnets, but the films' high resistance limits thermoelectric conversion efficiency. Combining Nernst and spin Seebeck effect in bulk materials would enable devices with simultaneously large transverse thermopower and low electrical resistance. Here we demonstrate experimentally that this is possible in composites of conducting ferromagnets (Ni or MnBi) containing metallic nanoparticles with strong spin–orbit interactions (Pt or Au). These materials display positive shifts in transverse thermopower attributable to inverse spin Hall electric fields in the nanoparticles. This more than doubles the power output of the Ni-Pt materials, establishing proof of principle that the spin Seebeck effect persists in bulk nanocomposites.
The spin Seebeck effect enables thermal-to-electrical energy conversion but the power generated in thin films remains low. Here, Boona et al. use composites of ferromagnetic conductors containing noble metal nanoparticles to show that the effect can enhance the transverse thermopower of bulk materials.
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Affiliation(s)
- Stephen R Boona
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210, USA
| | - Koen Vandaele
- Department of Inorganic and Physical Chemistry, Ghent University, Gent B-9000, Belgium
| | - Isabel N Boona
- Center for Electron Microscopy and Analysis, The Ohio State University, Columbus, Ohio 43212, USA.,Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210, USA
| | - David W McComb
- Center for Electron Microscopy and Analysis, The Ohio State University, Columbus, Ohio 43212, USA.,Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210, USA
| | - Joseph P Heremans
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210, USA.,Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
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48
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Spin-current probe for phase transition in an insulator. Nat Commun 2016; 7:12670. [PMID: 27573443 PMCID: PMC5013713 DOI: 10.1038/ncomms12670] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/20/2016] [Indexed: 11/10/2022] Open
Abstract
Spin fluctuation and transition have always been one of the central topics of magnetism and condensed matter science. Experimentally, the spin fluctuation is found transcribed onto scattering intensity in the neutron-scattering process, which is represented by dynamical magnetic susceptibility and maximized at phase transitions. Importantly, a neutron carries spin without electric charge, and therefore it can bring spin into a sample without being disturbed by electric energy. However, large facilities such as a nuclear reactor are necessary. Here we show that spin pumping, frequently used in nanoscale spintronic devices, provides a desktop microprobe for spin transition; spin current is a flux of spin without an electric charge and its transport reflects spin excitation. We demonstrate detection of antiferromagnetic transition in ultra-thin CoO films via frequency-dependent spin-current transmission measurements, which provides a versatile probe for phase transition in an electric manner in minute devices. Whilst neutron scattering is a powerful tool for studying spin fluctuations in materials, its availability is limited to large-scale user facilities. Here, the authors demonstrate how the pumping of pure spin currents can be used as a desktop probe to detect an antiferromagnetic transition.
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49
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Averyanov DV, Tokmachev AM, Karateeva CG, Karateev IA, Lobanovich EF, Prutskov GV, Parfenov OE, Taldenkov AN, Vasiliev AL, Storchak VG. Europium Silicide - a Prospective Material for Contacts with Silicon. Sci Rep 2016; 6:25980. [PMID: 27211700 PMCID: PMC4876492 DOI: 10.1038/srep25980] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 04/26/2016] [Indexed: 11/25/2022] Open
Abstract
Metal-silicon junctions are crucial to the operation of semiconductor devices: aggressive scaling demands low-resistive metallic terminals to replace high-doped silicon in transistors. It suggests an efficient charge injection through a low Schottky barrier between a metal and Si. Tremendous efforts invested into engineering metal-silicon junctions reveal the major role of chemical bonding at the interface: premier contacts entail epitaxial integration of metal silicides with Si. Here we present epitaxially grown EuSi2/Si junction characterized by RHEED, XRD, transmission electron microscopy, magnetization and transport measurements. Structural perfection leads to superb conductivity and a record-low Schottky barrier with n-Si while an antiferromagnetic phase invites spin-related applications. This development opens brand-new opportunities in electronics.
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Affiliation(s)
- Dmitry V Averyanov
- National Research Center "Kurchatov Institute", Kurchatov Square 1, Moscow 123182, Russia
| | - Andrey M Tokmachev
- National Research Center "Kurchatov Institute", Kurchatov Square 1, Moscow 123182, Russia
| | - Christina G Karateeva
- National Research Center "Kurchatov Institute", Kurchatov Square 1, Moscow 123182, Russia
| | - Igor A Karateev
- National Research Center "Kurchatov Institute", Kurchatov Square 1, Moscow 123182, Russia
| | - Eduard F Lobanovich
- National Research Center "Kurchatov Institute", Kurchatov Square 1, Moscow 123182, Russia
| | - Grigory V Prutskov
- National Research Center "Kurchatov Institute", Kurchatov Square 1, Moscow 123182, Russia
| | - Oleg E Parfenov
- National Research Center "Kurchatov Institute", Kurchatov Square 1, Moscow 123182, Russia
| | - Alexander N Taldenkov
- National Research Center "Kurchatov Institute", Kurchatov Square 1, Moscow 123182, Russia
| | - Alexander L Vasiliev
- National Research Center "Kurchatov Institute", Kurchatov Square 1, Moscow 123182, Russia
| | - Vyacheslav G Storchak
- National Research Center "Kurchatov Institute", Kurchatov Square 1, Moscow 123182, Russia
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50
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Lin W, Chen K, Zhang S, Chien CL. Enhancement of Thermally Injected Spin Current through an Antiferromagnetic Insulator. PHYSICAL REVIEW LETTERS 2016; 116:186601. [PMID: 27203336 DOI: 10.1103/physrevlett.116.186601] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Indexed: 06/05/2023]
Abstract
We report a large enhancement of thermally injected spin current in normal metal (NM)/antiferromagnet (AF)/yttrium iron garnet (YIG), where a thin AF insulating layer of NiO or CoO can enhance the spin current from YIG to a NM by up to a factor of 10. The spin current enhancement in NM/AF/YIG, with a pronounced maximum near the Néel temperature of the thin AF layer, has been found to scale linearly with the spin-mixing conductance at the NM/YIG interface for NM=3d, 4d, and 5d metals. Calculations of spin current enhancement and spin mixing conductance are qualitatively consistent with the experimental results.
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Affiliation(s)
- Weiwei Lin
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Kai Chen
- Department of Physics, University of Arizona, Tucson, Arizona 85721, USA
| | - Shufeng Zhang
- Department of Physics, University of Arizona, Tucson, Arizona 85721, USA
| | - C L Chien
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
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