1
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Dou P, Zhang J, Guo Y, Zhu T, Luo J, Zhao G, Huang H, Yu G, Zhao Y, Qi J, Deng X, Wang Y, Li J, Shen J, Zheng X, Wu Y, Yang H, Shen B, Wang S. Deterministic Magnetization Switching via Tunable Noncollinear Spin Configurations in Canted Magnets. NANO LETTERS 2023. [PMID: 37379096 DOI: 10.1021/acs.nanolett.3c01192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Spin obit torque (SOT) driven magnetization switching has been used widely for encoding consumption-efficient memory and logic. However, symmetry breaking under a magnetic field is required to realize the deterministic switching in synthetic antiferromagnets with perpendicular magnetic anisotropy (PMA), which limits their potential applications. Herein, we report all electric-controlled magnetization switching in the antiferromagnetic Co/Ir/Co trilayers with vertical magnetic imbalance. Besides, the switching polarity could be reversed by optimizing the Ir thickness. By using the polarized neutron reflection (PNR) measurements, the canted noncollinear spin configuration was observed in Co/Ir/Co trilayers, which results from the competition of magnetic inhomogeneity. In addition, the asymmetric domain walls demonstrated by micromagnetic simulations result from introducing imbalance magnetism, leading to the deterministic magnetization switching in Co/Ir/Co trilayers. Our findings highlight a promising route to electric-controlled magnetism via tunable spin configuration, improve our understanding of physical mechanisms, and significantly promote industrial applications in spintronic devices.
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Affiliation(s)
- Pengwei Dou
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jingyan Zhang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yaqin Guo
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Tao Zhu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jia Luo
- College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610068, China
| | - Guoping Zhao
- College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610068, China
| | - He Huang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yunchi Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jie Qi
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xiao Deng
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yuanbo Wang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jialiang Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jianxin Shen
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xinqi Zheng
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yanfei Wu
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Hongxin Yang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shouguo Wang
- School of Materials Science and Engineering, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
- School of Materials Science and Engineering, Anhui University, Hefei 230601, China
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2
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Xu T, Zhang Y, Wang Z, Bai H, Song C, Liu J, Zhou Y, Je SG, N'Diaye AT, Im MY, Yu R, Chen Z, Jiang W. Systematic Control of Ferrimagnetic Skyrmions via Composition Modulation in Pt/Fe 1-xTb x/Ta Multilayers. ACS NANO 2023; 17:7920-7928. [PMID: 37010987 DOI: 10.1021/acsnano.3c02006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Magnetic skyrmions are topological spin textures that can be used as memory and logic components for advancing the next generation spintronics. In this regard, control of nanoscale skyrmions, including their sizes and densities, is of particular importance for enhancing the storage capacity of skyrmionic devices. Here, we propose a viable route for engineering ferrimagnetic skyrmions via tuning the magnetic properties of the involved ferrimagnets Fe1-xTbx. Via tuning the composition of Fe1-xTbx that alters the magnetic anisotropy and the saturation magnetization, the size of the ferrimagnetic skyrmion (ds) and the average density (ηs) can be effectively tailored in [Pt/Fe1-xTbx/Ta]10 multilayers. In particular, a stabilization of sub-50 nm skyrmions with a high density is demonstrated at room temperature. Our work provides an effective approach for designing ferrimagnetic skyrmions with the desired size and density, which could be useful for enabling high-density ferrimagnetic skyrmionics.
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Affiliation(s)
- Teng Xu
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Yuxuan Zhang
- School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, MOE Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084, China
| | - Zidong Wang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
| | - Hao Bai
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Chengkun Song
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Jiahao Liu
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
| | - Yan Zhou
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
| | - Soong-Geun Je
- Lawrence Berkeley National Laboratory, Cyclotron Road, Berkeley, California 94720, United States
| | - Alpha T N'Diaye
- Lawrence Berkeley National Laboratory, Cyclotron Road, Berkeley, California 94720, United States
| | - Mi-Young Im
- Lawrence Berkeley National Laboratory, Cyclotron Road, Berkeley, California 94720, United States
| | - Rong Yu
- School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, MOE Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084, China
| | - Zhen Chen
- School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, MOE Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084, China
| | - Wanjun Jiang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
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3
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Dai B, Wu D, Razavi SA, Xu S, He H, Shu Q, Jackson M, Mahfouzi F, Huang H, Pan Q, Cheng Y, Qu T, Wang T, Tai L, Wong K, Kioussis N, Wang KL. Electric field manipulation of spin chirality and skyrmion dynamic. SCIENCE ADVANCES 2023; 9:eade6836. [PMID: 36791189 PMCID: PMC9931210 DOI: 10.1126/sciadv.ade6836] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 01/12/2023] [Indexed: 06/18/2023]
Abstract
The Dzyaloshinskii-Moriya interaction (DMI) is an antisymmetric exchange interaction that stabilizes spin chirality. One scientific and technological challenge is understanding and controlling the interaction between spin chirality and electric field. In this study, we investigate an unconventional electric field effect on interfacial DMI, skyrmion helicity, and skyrmion dynamics in a system with broken inversion symmetry. We design heterostructures with a 3d-5d atomic orbital interface to demonstrate the gate bias control of the DMI energy and thus transform the DMI between opposite chiralities. Furthermore, we use this voltage-controlled DMI (VCDMI) to manipulate the skyrmion spin texture. As a result, a type of intermediate skyrmion with a unique helicity is created, and its motion can be controlled and made to go straight. Our work shows the effective control of spin chirality, skyrmion helicity, and skyrmion dynamics by VCDMI. It promotes the emerging field of voltage-controlled chiral interactions and voltage-controlled skyrmionics.
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Affiliation(s)
- Bingqian Dai
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Di Wu
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Seyed Armin Razavi
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Shijie Xu
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Haoran He
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Qingyuan Shu
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Malcolm Jackson
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Farzad Mahfouzi
- Department of Physics and Astronomy, California State University, Northridge, Los Angeles, CA 91330-8268, USA
| | - Hanshen Huang
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Quanjun Pan
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yang Cheng
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tao Qu
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tianyi Wang
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Lixuan Tai
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kin Wong
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Nicholas Kioussis
- Department of Physics and Astronomy, California State University, Northridge, Los Angeles, CA 91330-8268, USA
| | - Kang L. Wang
- Departments of Electrical and Computer Engineering, Physics and Astronomy, and Material Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
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4
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Zhang W, Huang TX, Hehn M, Malinowski G, Verges M, Hohlfeld J, Remy Q, Lacour D, Wang XR, Zhao GP, Vallobra P, Xu Y, Mangin S, Zhao WS. Optical Creation of Skyrmions by Spin Reorientation Transition in Ferrimagnetic CoHo Alloys. ACS APPLIED MATERIALS & INTERFACES 2023; 15:5608-5619. [PMID: 36689950 DOI: 10.1021/acsami.2c19411] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Manipulating magnetic skyrmions by means of a femtosecond (fs) laser pulse has attracted great interest due to their promising applications in efficient information-storage devices with ultralow energy consumption. However, the mechanism underlying the creation of skyrmions induced by an fs laser is still lacking. As a result, a key challenge is to reveal the pathway for the massive reorientation of magnetization from trivial to nontrivial topological states. Here, we studied a series of ferrimagnetic CoHo alloys and investigated the effect of a single laser pulse on the magnetic states. Thanks to the time-resolved magneto-optical Kerr effect and imaging techniques, we demonstrate that the laser-induced phase transitions from single domains into a topological skyrmion phase are mediated by the transient in-plane magnetization state, in real time and space domains, respectively. Combining experiments and micromagnetic simulations, we propose a two-step process for creating skyrmions through laser pulse irradiation: (i) the electron temperature enhancement induces a spin reorientation transition on a picosecond (ps) timescale due to the suppression of perpendicular magnetic anisotropy (PMA) and (ii) the PMA slowly restores, accompanied by out-of-plane magnetization recovery, leading to the generation of skyrmions with the help of spin fluctuations. This work provides a route to control skyrmion patterns using an fs laser, thereby establishing the foundation for further exploration of topological magnetism at ultrafast timescales.
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Affiliation(s)
- Wei Zhang
- Anhui High Reliability Chips Engineering Laboratory, Hefei Innovation Research Institute, Beihang University, Hefei230013, China
- MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing100191, China
- CNRS, IJL, Université de Lorraine, NancyF-54000, France
| | | | - Michel Hehn
- CNRS, IJL, Université de Lorraine, NancyF-54000, France
| | | | - Maxime Verges
- CNRS, IJL, Université de Lorraine, NancyF-54000, France
| | | | - Quentin Remy
- CNRS, IJL, Université de Lorraine, NancyF-54000, France
| | - Daniel Lacour
- CNRS, IJL, Université de Lorraine, NancyF-54000, France
| | - Xin Ran Wang
- MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing100191, China
| | - Guo Ping Zhao
- College of Physics and Electronic Engineering and Institute of Solid State Physics, Sichuan Normal University, Chengdu610066, China
| | - Pierre Vallobra
- Anhui High Reliability Chips Engineering Laboratory, Hefei Innovation Research Institute, Beihang University, Hefei230013, China
| | - Yong Xu
- Anhui High Reliability Chips Engineering Laboratory, Hefei Innovation Research Institute, Beihang University, Hefei230013, China
- MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing100191, China
| | | | - Wei Sheng Zhao
- Anhui High Reliability Chips Engineering Laboratory, Hefei Innovation Research Institute, Beihang University, Hefei230013, China
- MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing100191, China
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5
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Xie X, Wang X, Wang W, Zhao X, Bai L, Chen Y, Tian Y, Yan S. Engineering Spin Configurations of Synthetic Antiferromagnet by Controlling Long-Range Oscillatory Interlayer Coupling and Neighboring Ferrimagnetic Coupling. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208275. [PMID: 36268544 DOI: 10.1002/adma.202208275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Controllable manipulation of specific spin configurations of magnetic materials is the key to constructing functional spintronic devices. Here, it is demonstrated by integrating the merits of ferromagnetic, ferrimagnetic, and antiferromagnetic spin configurations into one synthetic antiferromagnetic (SAF) heterostructure by controlling both long-range oscillatory interlayer coupling and neighboring ferrimagnetic coupling. A controllable manipulation of four types of spin configurations of the Pt/[Co/Pt/Co]/Ru/CoTb SAF heterostructures composed of ferromagnetic Co/Pt/Co and ferrimagnetic CoTb layers is successfully achieved. In particular, the compensated magnetization, enhanced anomalous Hall resistance in the remanence state, wide-temperature spin-orbit torque switching of magnetization, and high immunity to the external magnetic field are simultaneously obtained in one of the SAF heterojunctions with macroscopic interlayer antiferromagnetic coupling. This design concept of engineering spin configurations may enable efficient spin manipulation for customized memory and logic applications.
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Affiliation(s)
- Xuejie Xie
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Xiujuan Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Wei Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Xiaonan Zhao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Lihui Bai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Yanxue Chen
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Yufeng Tian
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
| | - Shishen Yan
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, P. R. China
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6
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Zuo S, Qiao K, Zhang Y, Li Z, Zhao T, Jiang C, Shen B. Spontaneous Topological States and Their Mutual Transformations in a Rare-Earth Ferrimagnet. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205574. [PMID: 36403248 PMCID: PMC9875609 DOI: 10.1002/advs.202205574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/02/2022] [Indexed: 06/16/2023]
Abstract
Nontrivial chiral spin textures with nanometric sizes and novel characteristics (e.g., magnetic skyrmions) are promising for encoding information bits in future energy-efficient and high-density spintronic devices. Because of antiferromagnetic exchange coupling, skyrmions in ferrimagnetic materials exhibit many advantages in terms of size and efficient manipulation, which allow them to overcome the limitations of ferromagnetic skyrmions. Despite recent progress, ferrimagnetic skyrmions have been observed only in few films in the presence of external fields, while those in ferrimagnetic bulks remain elusive. This study reports on spontaneously generated zero-field ground-state magnetic skyrmions and their subsequent transformation into traditional magnetic bubbles via intermediate states of (bi-)target bubbles during a magnetic anisotropy change in the rare-earth ferrimagnetic crystal DyFe11 Ti. Spontaneous reversible topological transformation driven by a temperature-induced spin reorientation transition is directly distinguished using Lorentz transmission electron microscopy. The spontaneous generation of magnetic skyrmions and successive topological transformations in ferrimagnetic DyFe11 Ti are expected to advance the design of topological spin textures with versatile properties and potential applications in rare-earth magnets.
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Affiliation(s)
- Shulan Zuo
- Key Laboratory of Aerospace Materials and Performance (Ministry of Education)School of Materials Science and EngineeringBeihang UniversityBeijing100191P. R. China
| | - Kaiming Qiao
- School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing100083P. R. China
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190P. R. China
- Songshan Lake Materials LaboratoryDongguanGuangdong523808P. R. China
| | - Zhuolin Li
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190P. R. China
| | - Tongyun Zhao
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190P. R. China
| | - Chengbao Jiang
- Key Laboratory of Aerospace Materials and Performance (Ministry of Education)School of Materials Science and EngineeringBeihang UniversityBeijing100191P. R. China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190P. R. China
- Ningbo Institute of Materials Technology & EngineeringChinese Academy of SciencesNingboZhejiang315201P. R. China
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7
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Ukleev V, Luo C, Abrudan R, Aqeel A, Back CH, Radu F. Chiral surface spin textures in Cu 2OSeO 3 unveiled by soft X-ray scattering in specular reflection geometry. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2022; 23:682-690. [PMID: 36277505 PMCID: PMC9586675 DOI: 10.1080/14686996.2022.2131466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 09/23/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Resonant elastic soft X-ray magnetic scattering (XRMS) is a powerful tool to explore long-periodic spin textures in single crystals. However, due to the limited momentum transfer range imposed by long wavelengths of photons in the soft x-ray region, Bragg diffraction is restricted to crystals with the large lattice parameters. Alternatively, small-angle X-ray scattering has been involved in the soft energy X-ray range which, however, brings in difficulties with the sample preparation that involves focused ion beam milling to thin down the crystal to below a few hundred nm thickness. We show how to circumvent these restrictions using XRMS in specular reflection from a sub-nanometer smooth crystal surface. The method allows observing diffraction peaks from the helical and conical spin modulations at the surface of a Cu 2 OSeO 3 single crystal and probing their corresponding chirality as contributions to the dichroic scattered intensity. The results suggest a promising way to carry out XRMS studies on a plethora of noncentrosymmetric systems hitherto unexplored with soft X-rays due to the absence of the commensurate Bragg peaks in the available momentum transfer range.
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Affiliation(s)
- V. Ukleev
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - C. Luo
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
- Physik-Department, Technische Universität München, Garching, Germany
| | - R. Abrudan
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - A. Aqeel
- Physik-Department, Technische Universität München, Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), München, Germany
| | - C. H. Back
- Physik-Department, Technische Universität München, Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), München, Germany
| | - F. Radu
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
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8
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Ding S, Chen C, Cao Z, Wang D, Pan Y, Tao R, Zhao D, Hu Y, Jiang T, Yan Y, Shi Z, Wan X, Feng D, Zhang T. Observation of robust zero-energy state and enhanced superconducting gap in a trilayer heterostructure of MnTe/Bi 2Te 3/Fe(Te, Se). SCIENCE ADVANCES 2022; 8:eabq4578. [PMID: 36103530 PMCID: PMC9473575 DOI: 10.1126/sciadv.abq4578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 07/28/2022] [Indexed: 06/15/2023]
Abstract
The interface between magnetic material and superconductors has long been predicted to host unconventional superconductivity, such as spin-triplet pairing and topological nontrivial pairing state, particularly when spin-orbital coupling (SOC) is incorporated. To identify these unconventional pairing states, fabricating homogenous heterostructures that contain such various properties are preferred but often challenging. Here, we synthesized a trilayer-type van der Waals heterostructure of MnTe/Bi2Te3/Fe(Te, Se), which combined s-wave superconductivity, thickness-dependent magnetism, and strong SOC. Via low-temperature scanning tunneling microscopy, we observed robust zero-energy states with notably nontrivial properties and an enhanced superconducting gap size on single unit cell (UC) MnTe surface. In contrast, no zero-energy state was observed on 2-UC MnTe. First-principle calculations further suggest that the 1-UC MnTe has large interfacial Dzyaloshinskii-Moriya interaction and a frustrated AFM state, which could promote noncolinear spin textures. It thus provides a promising platform for exploring topological nontrivial superconductivity.
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Affiliation(s)
- Shuyue Ding
- Department of Physics, State Key Laboratory of Surface Physics and Advanced Material Laboratory, Fudan University, Shanghai 200438, China
| | - Chen Chen
- Department of Physics, State Key Laboratory of Surface Physics and Advanced Material Laboratory, Fudan University, Shanghai 200438, China
| | - Zhipeng Cao
- National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
| | - Di Wang
- National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
| | - Yongqiang Pan
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China
| | - Ran Tao
- Department of Physics, State Key Laboratory of Surface Physics and Advanced Material Laboratory, Fudan University, Shanghai 200438, China
| | - Dongming Zhao
- Department of Physics, State Key Laboratory of Surface Physics and Advanced Material Laboratory, Fudan University, Shanghai 200438, China
| | - Yining Hu
- Department of Physics, State Key Laboratory of Surface Physics and Advanced Material Laboratory, Fudan University, Shanghai 200438, China
| | - Tianxing Jiang
- Department of Physics, State Key Laboratory of Surface Physics and Advanced Material Laboratory, Fudan University, Shanghai 200438, China
| | - Yajun Yan
- Department of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Zhixiang Shi
- School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189, China
| | - Xiangang Wan
- National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - Donglai Feng
- Department of Physics, University of Science and Technology of China, Hefei 230026, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Tong Zhang
- Department of Physics, State Key Laboratory of Surface Physics and Advanced Material Laboratory, Fudan University, Shanghai 200438, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
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9
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Bindal N, Nisar A, Dhull S, Kaushik BK. Magnetic Skyrmions: Recent advances and applications. IEEE NANOTECHNOLOGY MAGAZINE 2021. [DOI: 10.1109/mnano.2021.3113215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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10
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Abstract
Giant spin-orbit torque (SOT) from topological insulators (TIs) provides an energy efficient writing method for magnetic memory, which, however, is still premature for practical applications due to the challenge of the integration with magnetic tunnel junctions (MTJs). Here, we demonstrate a functional TI-MTJ device that could become the core element of the future energy-efficient spintronic devices, such as SOT-based magnetic random-access memory (SOT-MRAM). The state-of-the-art tunneling magnetoresistance (TMR) ratio of 102% and the ultralow switching current density of 1.2 × 105 A cm−2 have been simultaneously achieved in the TI-MTJ device at room temperature, laying down the foundation for TI-driven SOT-MRAM. The charge-spin conversion efficiency θSH in TIs is quantified by both the SOT-induced shift of the magnetic switching field (θSH = 1.59) and the SOT-induced ferromagnetic resonance (ST-FMR) (θSH = 1.02), which is one order of magnitude larger than that in conventional heavy metals. These results inspire a revolution of SOT-MRAM from classical to quantum materials, with great potential to further reduce the energy consumption. It remains challenging to integrate topological insulators (TI) with magnetic tunnel junctions (MTJ) for spintronics applications. Here, the authors achieve a large tunneling magnetoresistance ratio and a low switching current density in a TI-MTJ device at room temperature, very promising for TI-driven magnetic memory.
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11
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Zhang X, Ambhire SC, Lu Q, Niu W, Cook J, Jiang JS, Hong D, Alahmed L, He L, Zhang R, Xu Y, Zhang SSL, Li P, Bian G. Giant Topological Hall Effect in van der Waals Heterostructures of CrTe 2/Bi 2Te 3. ACS NANO 2021; 15:15710-15719. [PMID: 34460216 DOI: 10.1021/acsnano.1c05519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Discoveries of the interfacial topological Hall effect (THE) provide an ideal platform for exploring the physics arising from the interplay between topology and magnetism. The interfacial topological Hall effect is closely related to the Dzyaloshinskii-Moriya interaction (DMI) at an interface and topological spin textures. However, it is difficult to achieve a sizable THE in heterostructures due to the stringent constraints on the constituents of THE heterostructures, such as strong spin-orbit coupling (SOC). Here, we report the observation of a giant THE signal of 1.39 μΩ·cm in the van der Waals heterostructures of CrTe2/Bi2Te3 fabricated by molecular beam epitaxy, a prototype of two-dimensional (2D) ferromagnet (FM)/topological insulator (TI). This large magnitude of THE is attributed to an optimized combination of 2D ferromagnetism in CrTe2, strong SOC in Bi2Te3, and an atomically sharp interface. Our work reveals CrTe2/Bi2Te3 as a convenient platform for achieving large interfacial THE in hybrid systems, which could be utilized to develop quantum science and high-density information storage devices.
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Affiliation(s)
- Xiaoqian Zhang
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Siddhesh C Ambhire
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Qiangsheng Lu
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Wei Niu
- New Energy Technology Engineering Laboratory of Jiangsu Provence & School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Jacob Cook
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Jidong Samuel Jiang
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Deshun Hong
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Laith Alahmed
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Liang He
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Rong Zhang
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Yongbing Xu
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
- York-Nanjing Joint Centre (YNJC) for spintronics and nano engineering, Department of Electronic Engineering, The University of York, York YO10 3DD, United Kingdom
| | - Steven S-L Zhang
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Peng Li
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Guang Bian
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
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12
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Liu J, Hesjedal T. Magnetic Topological Insulator Heterostructures: A Review. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021:e2102427. [PMID: 34665482 DOI: 10.1002/adma.202102427] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/05/2021] [Indexed: 06/13/2023]
Abstract
Topological insulators (TIs) provide intriguing prospects for the future of spintronics due to their large spin-orbit coupling and dissipationless, counter-propagating conduction channels in the surface state. The combination of topological properties and magnetic order can lead to new quantum states including the quantum anomalous Hall effect that was first experimentally realized in Cr-doped (Bi,Sb)2 Te3 films. Since magnetic doping can introduce detrimental effects, requiring very low operational temperatures, alternative approaches are explored. Proximity coupling to magnetically ordered systems is an obvious option, with the prospect to raise the temperature for observing the various quantum effects. Here, an overview of proximity coupling and interfacial effects in TI heterostructures is presented, which provides a versatile materials platform for tuning the magnetic and topological properties of these exciting materials. An introduction is first given to the heterostructure growth by molecular beam epitaxy and suitable structural, electronic, and magnetic characterization techniques. Going beyond transition-metal-doped and undoped TI heterostructures, examples of heterostructures are discussed, including rare-earth-doped TIs, magnetic insulators, and antiferromagnets, which lead to exotic phenomena such as skyrmions and exchange bias. Finally, an outlook on novel heterostructures such as intrinsic magnetic TIs and systems including 2D materials is given.
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Affiliation(s)
- Jieyi Liu
- Clarendon Laboratory, Department of Physics University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Thorsten Hesjedal
- Clarendon Laboratory, Department of Physics University of Oxford, Parks Road, Oxford, OX1 3PU, UK
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13
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Bhattacharyya S, Akhgar G, Gebert M, Karel J, Edmonds MT, Fuhrer MS. Recent Progress in Proximity Coupling of Magnetism to Topological Insulators. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2007795. [PMID: 34185344 DOI: 10.1002/adma.202007795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/11/2021] [Indexed: 05/08/2023]
Abstract
Inducing long-range magnetic order in 3D topological insulators can gap the Dirac-like metallic surface states, leading to exotic new phases such as the quantum anomalous Hall effect or the axion insulator state. These magnetic topological phases can host robust, dissipationless charge and spin currents or unique magnetoelectric behavior, which can be exploited in low-energy electronics and spintronics applications. Although several different strategies have been successfully implemented to realize these states, to date these phenomena have been confined to temperatures below a few Kelvin. This review focuses on one strategy: inducing magnetic order in topological insulators by proximity of magnetic materials, which has the capability for room temperature operation, unlocking the potential of magnetic topological phases for applications. The unique advantages of this strategy, the important physical mechanisms facilitating magnetic proximity effect, and the recent progress to achieve, understand, and harness proximity-coupled magnetic order in topological insulators are discussed. Some emerging new phenomena and applications enabled by proximity coupling of magnetism and topological materials, such as skyrmions and the topological Hall effect, are also highlighted, and the authors conclude with an outlook on remaining challenges and opportunities in the field.
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Affiliation(s)
- Semonti Bhattacharyya
- School of Physics and Astronomy, Monash University, Victoria, 3800, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria, 3800, Australia
| | - Golrokh Akhgar
- School of Physics and Astronomy, Monash University, Victoria, 3800, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria, 3800, Australia
| | - Matthew Gebert
- School of Physics and Astronomy, Monash University, Victoria, 3800, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria, 3800, Australia
| | - Julie Karel
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria, 3800, Australia
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Mark T Edmonds
- School of Physics and Astronomy, Monash University, Victoria, 3800, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria, 3800, Australia
| | - Michael S Fuhrer
- School of Physics and Astronomy, Monash University, Victoria, 3800, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria, 3800, Australia
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