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Luan J, Feng Y, Ji Y, Li Y, Li H, Liu Z, Liu C, Zhang J, Kou X, Wang Y. Controlling the Zero Hall Plateau in a Quantum Anomalous Hall Insulator by In-Plane Magnetic Field. PHYSICAL REVIEW LETTERS 2023; 130:186201. [PMID: 37204911 DOI: 10.1103/physrevlett.130.186201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 04/07/2023] [Indexed: 05/21/2023]
Abstract
We investigate the quantum anomalous Hall plateau transition in the presence of independent out-of-plane and in-plane magnetic fields. The perpendicular coercive field, zero Hall plateau width, and peak resistance value can all be systematically controlled by the in-plane magnetic field. The traces taken at various fields almost collapse into a single curve when the field vector is renormalized to an angle as a geometric parameter. These results can be explained consistently by the competition between magnetic anisotropy and in-plane Zeeman field, and the close relationship between quantum transport and magnetic domain structure. The accurate control of zero Hall plateau facilitates the search for chiral Majorana modes based on the quantum anomalous Hall system in proximity to a superconductor.
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Affiliation(s)
- Jianli Luan
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Yang Feng
- Beijing Academy of Quantum Information Sciences, Beijing 100193, People's Republic of China
| | - Yuchen Ji
- ShanghaiTech Laboratory for Topological Physics, School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Yuanzhao Li
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Hangzhe Li
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Zhongkai Liu
- ShanghaiTech Laboratory for Topological Physics, School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Chang Liu
- Beijing Academy of Quantum Information Sciences, Beijing 100193, People's Republic of China
| | - Jinsong Zhang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Frontier Science Center for Quantum Information, Beijing 100084, People's Republic of China
- Hefei National Laboratory, Hefei 230088, People's Republic of China
| | - Xufeng Kou
- ShanghaiTech Laboratory for Topological Physics, School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
- School of Information Science and Technology, ShanghaiTech University, Shanghai 20031, People's Republic of China
| | - Yayu Wang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Frontier Science Center for Quantum Information, Beijing 100084, People's Republic of China
- Hefei National Laboratory, Hefei 230088, People's Republic of China
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2
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Xie H, Chen X, Zhang Q, Mu Z, Zhang X, Yan B, Wu Y. Magnetization switching in polycrystalline Mn 3Sn thin film induced by self-generated spin-polarized current. Nat Commun 2022; 13:5744. [PMID: 36180425 PMCID: PMC9525633 DOI: 10.1038/s41467-022-33345-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 09/13/2022] [Indexed: 11/13/2022] Open
Abstract
Electrical manipulation of spins is essential to design state-of-the-art spintronic devices and commonly relies on the spin current injected from a second heavy-metal material. The fact that chiral antiferromagnets produce spin current inspires us to explore the magnetization switching of chiral spins using self-generated spin torque. Here, we demonstrate the electric switching of noncollinear antiferromagnetic state in Mn3Sn by observing a crossover from conventional spin-orbit torque to the self-generated spin torque when increasing the MgO thickness in Ta/MgO/Mn3Sn polycrystalline films. The spin current injection from the Ta layer can be controlled and even blocked by varying the MgO thickness, but the switching sustains even at a large MgO thickness. Furthermore, the switching polarity reverses when the MgO thickness exceeds around 3 nm, which cannot be explained by the spin-orbit torque scenario due to spin current injection from the Ta layer. Evident current-induced switching is also observed in MgO/Mn3Sn and Ti/Mn3Sn bilayers, where external injection of spin Hall current to Mn3Sn is negligible. The inter-grain spin-transfer torque induced by spin-polarized current explains the experimental observations. Our findings provide an alternative pathway for electrical manipulation of non-collinear antiferromagnetic state without resorting to the conventional bilayer structure. Under an applied current, chiral antiferromagnets, such as Mn3Sn, can produce a spin-polarized current. Here, by varying the thickness of a buffering layer, the authors show that this spin-polarized current can drive self-induced switching in polycrystalline Mn3Sn.
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Affiliation(s)
- Hang Xie
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore
| | - Xin Chen
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore
| | - Qi Zhang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore.,Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Xueyuan Rd. 1088, Shenzhen, 518055, China
| | - Zhiqiang Mu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Xinhai Zhang
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Xueyuan Rd. 1088, Shenzhen, 518055, China
| | - Binghai Yan
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel.
| | - Yihong Wu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore.
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3
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He W, Wan C, Zheng C, Wang Y, Wang X, Ma T, Wang Y, Guo C, Luo X, Stebliy ME, Yu G, Liu Y, Ognev AV, Samardak AS, Han X. Field-Free Spin-Orbit Torque Switching Enabled by the Interlayer Dzyaloshinskii-Moriya Interaction. NANO LETTERS 2022; 22:6857-6865. [PMID: 35849087 DOI: 10.1021/acs.nanolett.1c04786] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Perpendicularly magnetized structures that are switchable using a spin current under field-free conditions can potentially be applied in spin-orbit torque magnetic random-access memory (SOT-MRAM). Several structures have been developed; however, new structures with a simple stack structure and MRAM compatibility are urgently needed. Herein, a typical structure in a perpendicular spin-transfer torque MRAM, the Pt/Co multilayer and its synthetic antiferromagnetic counterpart with perpendicular magnetic anisotropy, was observed to possess an intrinsic interlayer chiral interaction between neighboring magnetic layers, namely, the interlayer Dzyaloshinskii-Moriya interaction (DMI) effect. Furthermore, using a current parallel to the eigenvector of the interlayer DMI, we switched the perpendicular magnetization of both structures without a magnetic field, owing to the additional symmetry breaking introduced by the interlayer DMI. This SOT switching scheme realized in the Pt/Co multilayer and its synthetic antiferromagnet structure may open a new avenue toward practical perpendicular SOT-MRAM and other SOT devices.
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Affiliation(s)
- Wenqing He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Caihua Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Cuixiu Zheng
- School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yizhan Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiao Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Tianyi Ma
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Yuqiang Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Chenyang Guo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Xuming Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
| | - Maksim E Stebliy
- Laboratory of Spin-Orbitronics, Institute of High Technologies and Advanced Materials, Far Eastern Federal University, Vladivostok 690922, Russia
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Yaowen Liu
- School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Alexey V Ognev
- Laboratory of Spin-Orbitronics, Institute of High Technologies and Advanced Materials, Far Eastern Federal University, Vladivostok 690922, Russia
| | - Alexander S Samardak
- Laboratory of Spin-Orbitronics, Institute of High Technologies and Advanced Materials, Far Eastern Federal University, Vladivostok 690922, Russia
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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4
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Wang WH, Pan CY, Liu CM, Lin WC, Jiang PH. Chirality-Induced Noncollinear Magnetization and Asymmetric Domain-Wall Propagation in Hydrogenated CoPd Thin Films. ACS APPLIED MATERIALS & INTERFACES 2022; 14:20151-20158. [PMID: 35468278 DOI: 10.1021/acsami.1c23276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Array-patterned CoPd-based heterostructures are created through e-beam lithography and plasma pretreatment that induces oxidation with depth gradient in the CoPd alloy films, breaking the central symmetry of the structure. Effects on the magnetic properties of the follow-up hydrogenation of the thin film are observed via magneto-optic Kerr effect microscopy. The system exhibits a strong vertical and lateral antiferromagnetic coupling in the perpendicular component between the areas with and without plasma pretreatment, and asymmetric domain-wall propagation in the plasma-pretreated areas during magnetization reversal. These phenomena exhibit evident magnetic chirality and can be interpreted with the Ruderman-Kittel-Kasuya-Yosida coupling and the Dzyaloshinskii-Moriya interaction (DMI). The sample processing demonstrated in this study allows easy incorporation of lithography techniques that can define areas with or without DMI to create intricate magnetic patterns on the sample, which provides an avenue toward more sophisticated control of canted spin textures in future spintronic devices.
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Affiliation(s)
- Wei-Hsiang Wang
- Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan
- Department of Physics, National Sun Yat-sen University, Kaohsiung 804, Taiwan
| | - Ching-Yang Pan
- Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan
| | - Chak-Ming Liu
- Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan
| | - Wen-Chin Lin
- Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan
| | - Pei-Hsun Jiang
- Department of Physics, National Taiwan Normal University, Taipei 116, Taiwan
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5
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Jiang L, Huang C, Zhu Y, Pan Y, Fan J, Zhang K, Ma C, Shi D, Zhang H. Tuning the size of skyrmion by strain at the Co/Pt3 Interfaces. iScience 2022; 25:104039. [PMID: 35330683 PMCID: PMC8938285 DOI: 10.1016/j.isci.2022.104039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 02/09/2022] [Accepted: 03/03/2022] [Indexed: 11/25/2022] Open
Abstract
Based on density functional theory calculations, we elucidated the tunability of the atomic structures and magnetic interactions of Co/Pt3 interface (one layer of hcp(0001) Co and three layers of fcc(111) Pt) and thus the skyrmion sizes using strain. The dispersion relations of the spin spiral in the opposite directions, E(q) and E(-q), were evaluated based on generalized Bloch equations. Effective exchange coupling (EC) and Dzyaloshinsky-Moriya interaction (DMI) parameters between different neighbors Ji and di at different lattice constants were derived by fitting the resulting spin spiral dispersion E(q) to EC model with DMI and E(q)-E(-q) formula, respectively. We observed an increase in DMI and a significant decrease in EC with an increase in strain. Hence, the size of Néel-type skyrmions determined by the ratio of EC/DMI can be controlled by applying strain, leading to an effective approach to tailor the formation of skyrmion lattices by inducing slight structural modifications on the magnetic thin films. Calculate the EC and DMI of multi-nearest neighbors in the VASP program Show detailed changes of multi-nearest neighboring EC and DMI with deformation The size of skyrmion does decrease as the lattice constant increases Distance between Co and Pt layer determines the size of DMI
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Wu H, Nance J, Razavi SA, Lujan D, Dai B, Liu Y, He H, Cui B, Wu D, Wong K, Sobotkiewich K, Li X, Carman GP, Wang KL. Chiral Symmetry Breaking for Deterministic Switching of Perpendicular Magnetization by Spin-Orbit Torque. NANO LETTERS 2021; 21:515-521. [PMID: 33338380 DOI: 10.1021/acs.nanolett.0c03972] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Symmetry breaking is a characteristic to determine which branch of a bifurcation system follows upon crossing a critical point. Specifically, in spin-orbit torque (SOT) devices, a fundamental question arises: how can the symmetry of the perpendicular magnetic moment be broken by the in-plane spin polarization? Here, we show that the chiral symmetry breaking by the antisymmetric Dzyaloshinskii-Moriya interaction (DMI) can induce the deterministic SOT switching of the perpendicular magnetization. By introducing a gradient of saturation magnetization or magnetic anisotropy, the dynamic noncollinear spin textures are formed under the current-driven SOT, and thus, the chiral symmetry of these dynamic spin textures is broken by the DMI, resulting in the deterministic magnetization switching. We introduce a strategy to induce an out-of-plane (z) gradient of magnetic properties as a practical solution for the wafer-scale manufacture of SOT devices.
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Affiliation(s)
- Hao Wu
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - John Nance
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, United States
| | - Seyed Armin Razavi
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - David Lujan
- Department of Physics, and Center for Complex Quantum Systems, The University of Texas at Austin, Texas 78712, United States
| | - Bingqian Dai
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Yuxiang Liu
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Haoran He
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Baoshan Cui
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Di Wu
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Kin Wong
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Kemal Sobotkiewich
- Department of Physics, and Center for Complex Quantum Systems, The University of Texas at Austin, Texas 78712, United States
| | - Xiaoqin Li
- Department of Physics, and Center for Complex Quantum Systems, The University of Texas at Austin, Texas 78712, United States
| | - Gregory P Carman
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, United States
| | - Kang L Wang
- Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
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7
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Strain-enhanced Dzyaloshinskii-Moriya interaction at Co/Pt interfaces. Sci Rep 2020; 10:12314. [PMID: 32704010 PMCID: PMC7378838 DOI: 10.1038/s41598-020-69360-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/10/2020] [Indexed: 11/08/2022] Open
Abstract
The interfacial Dzyaloshinskii-Moriya interaction (DMI) is an essential ingredient for stabilizing chiral spin configurations in spintronic applications. Here, via first-principles calculations, we reveal the influence of lattice strain on DMI in Co/Pt interface. We observed a considerable enhancement for a certain lattice strain. Furthermore, a direct correlation is established between the DMI and interlayer distances dominated by the strain, which is attributed to a hybridization of electronic orbitals. This hybridization has also been presented as the microscopic origin of the interfacial DMI. We anticipate that our predictions provide new insights into the control of interfacial DMI for skyrmion-based spintronic devices.
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8
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Quessab Y, Xu JW, Ma CT, Zhou W, Riley GA, Shaw JM, Nembach HT, Poon SJ, Kent AD. Tuning interfacial Dzyaloshinskii-Moriya interactions in thin amorphous ferrimagnetic alloys. Sci Rep 2020; 10:7447. [PMID: 32366864 PMCID: PMC7198596 DOI: 10.1038/s41598-020-64427-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 04/15/2020] [Indexed: 11/26/2022] Open
Abstract
Skyrmions can be stabilized in magnetic systems with broken inversion symmetry and chiral interactions, such as Dzyaloshinskii-Moriya interactions (DMI). Further, compensation of magnetic moments in ferrimagnetic materials can significantly reduce magnetic dipolar interactions, which tend to favor large skyrmions. Tuning DMI is essential to control skyrmion properties, with symmetry breaking at interfaces offering the greatest flexibility. However, in contrast to the ferromagnet case, few studies have investigated interfacial DMI in ferrimagnets. Here we present a systematic study of DMI in ferrimagnetic CoGd films by Brillouin light scattering. We demonstrate the ability to control DMI by the CoGd cap layer composition, the stack symmetry and the ferrimagnetic layer thickness. The DMI thickness dependence confirms its interfacial nature. In addition, magnetic force microscopy reveals the ability to tune DMI in a range that stabilizes sub-100 nm skyrmions at room temperature in zero field. Our work opens new paths for controlling interfacial DMI in ferrimagnets to nucleate and manipulate skyrmions.
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Affiliation(s)
- Y Quessab
- Center for Quantum Phenomena, Department of Physics, New York University, New York, New York, 10003, USA.
| | - J-W Xu
- Center for Quantum Phenomena, Department of Physics, New York University, New York, New York, 10003, USA
| | - C T Ma
- Department of Physics, University of Virginia, Charlottesville, Virginia, 22904, USA
| | - W Zhou
- Department of Physics, University of Virginia, Charlottesville, Virginia, 22904, USA
| | - G A Riley
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, Colorado, 80305, USA
- Center for Memory and Recording Research, University of California San Diego, La Jolla, California, 92093, USA
| | - J M Shaw
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, Colorado, 80305, USA
| | - H T Nembach
- Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, Colorado, 80305, USA
- JILA, University of Colorado, Boulder, Colorado, 80309, USA
| | - S J Poon
- Department of Physics, University of Virginia, Charlottesville, Virginia, 22904, USA
| | - A D Kent
- Center for Quantum Phenomena, Department of Physics, New York University, New York, New York, 10003, USA
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9
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Li S, Wang Z, Wang Y, Wang M, Zhao W. Magnetization Dynamics Modulated by Dzyaloshinskii-Moriya Interaction in the Double-Interface Spin-Transfer Torque Magnetic Tunnel Junction. NANOSCALE RESEARCH LETTERS 2019; 14:315. [PMID: 31522317 PMCID: PMC6745041 DOI: 10.1186/s11671-019-3150-4] [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: 07/06/2019] [Accepted: 09/06/2019] [Indexed: 06/10/2023]
Abstract
Currently double-interface magnetic tunnel junctions (MTJs) have been developed for enhancing the thermal stability barrier at the nanoscale technology node. Dzyaloshinskii-Moriya interaction (DMI) inevitably exists in such devices due to the use of the heavy-metal/ferromagnet structures. Previous studies have demonstrated the detrimental effect of DMI on the conventional single-interface spin-transfer torque (STT) MTJs. Here, in this work, we will prove that the detrimental effect of DMI could be almost eliminated in the double-interface STT-MTJ. This conclusion is attributed to the suppressing effect of Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction on the DMI. Detailed mechanisms are analyzed based on the theoretical models and micromagnetic simulation results. Our work highlights the importance of appropriately controlling the DMI in the composite free layer of the double-interface STT-MTJ.
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Affiliation(s)
- Simin Li
- School of Microelectronics, Fert Beijing Research Institute, School of Electronics and Information Engineering, Beihang University, Beijing, 100191, China
| | - Zhaohao Wang
- School of Microelectronics, Fert Beijing Research Institute, School of Electronics and Information Engineering, Beihang University, Beijing, 100191, China.
- Beijing Advanced Innovation Center for Big Data and Brain Computing (BDBC), Beihang University, Beijing, 100191, China.
- Beihang-Geortek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao, 266100, China.
| | - Yijie Wang
- School of Beijing, Beihang University, Beijing, 100191, China
| | - Mengxing Wang
- School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, 100191, China
| | - Weisheng Zhao
- School of Microelectronics, Fert Beijing Research Institute, School of Electronics and Information Engineering, Beihang University, Beijing, 100191, China.
- Beijing Advanced Innovation Center for Big Data and Brain Computing (BDBC), Beihang University, Beijing, 100191, China.
- Beihang-Geortek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao, 266100, China.
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10
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Dao TP, Müller M, Luo Z, Baumgartner M, Hrabec A, Heyderman LJ, Gambardella P. Chiral Domain Wall Injector Driven by Spin-Orbit Torques. NANO LETTERS 2019; 19:5930-5937. [PMID: 31419382 DOI: 10.1021/acs.nanolett.9b01504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Memory and logic devices that encode information in magnetic domains rely on the controlled injection of domain walls to reach their full potential. In this work, we exploit the chiral coupling, which is induced by the Dzyaloshinskii-Moriya interaction, between in-plane and out-of-plane magnetized regions of a Pt/Co/AlOx trilayer in combination with current-driven spin-orbit torques to control the injection of domain walls into magnetic conduits. We demonstrate that the current-induced domain nucleation is strongly inhibited for magnetic configurations stabilized by the chiral coupling and promoted for those that have the opposite chirality. These configurations allow for efficient domain wall injection using current densities of the order of 4 × 1011 A m-2, which are lower than those used in other injection schemes. Furthermore, by setting the orientation of the in-plane magnetization using an external field, we demonstrate the use of a chiral domain wall injector to create a controlled sequence of alternating domains in a racetrack structure driven by a steady stream of unipolar current pulses.
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Affiliation(s)
- T Phuong Dao
- Laboratory for Magnetism and Interface Physics, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
- Laboratory for Multiscale Materials Experiments , Paul Scherrer Institute , 5232 Villigen PSI , Switzerland
| | - Marvin Müller
- Laboratory for Magnetism and Interface Physics, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
- Laboratory for Multifunctional Ferroic Materials, Department of Materials , ETH Zürich , 8093 Zurich , Switzerland
| | - Zhaochu Luo
- Laboratory for Mesoscopic Systems, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
- Laboratory for Multiscale Materials Experiments , Paul Scherrer Institute , 5232 Villigen PSI , Switzerland
| | - Manuel Baumgartner
- Laboratory for Magnetism and Interface Physics, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
| | - Aleš Hrabec
- Laboratory for Magnetism and Interface Physics, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
- Laboratory for Multiscale Materials Experiments , Paul Scherrer Institute , 5232 Villigen PSI , Switzerland
| | - Laura J Heyderman
- Laboratory for Mesoscopic Systems, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
- Laboratory for Multiscale Materials Experiments , Paul Scherrer Institute , 5232 Villigen PSI , Switzerland
| | - Pietro Gambardella
- Laboratory for Magnetism and Interface Physics, Department of Materials , ETH Zurich , 8093 Zurich , Switzerland
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11
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Zhao X, Zhang X, Yang H, Cai W, Zhao Y, Wang Z, Zhao W. Ultra-efficient spin-orbit torque induced magnetic switching in W/CoFeB/MgO structures. NANOTECHNOLOGY 2019; 30:335707. [PMID: 31018193 DOI: 10.1088/1361-6528/ab1c02] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Spin-orbit torque (SOT) induced magnetic switching in heavy metal/ferromagnet structures with perpendicular magnetic anisotropy (PMA) is promising for energy efficient spintronic devices. Here, we studied the SOT induced magnetic switching in perpendicular W/Co20Fe60B20/MgO structures. We demonstrated the critical current density for the SOT induced switching is as low as 1.15 × 106 A cm-2 in the presence of an in-plane magnetic field, which is very energy efficient in terms of magnetic switching. We attribute this ultra-efficient magnetic switching to the high spin Hall angle of the W layer and the ultra-low domain wall pinning field of the CoFeB. The SOT induced switching procedure was directly observed by a high-resolution Kerr microscopy. Furthermore, the weak Dzyaloshinsky-Moriya interactions are shown to be favorable for switching. Our experiments physically explained the ultra-efficient SOT induced magnetic switching in W/CoFeB/MgO structures, and direct observation of the switching procedure can improve the comprehensive understanding of this dynamic process and further promote the study of SOT based memory devices.
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Affiliation(s)
- Xiaoxuan Zhao
- Fert Beijing Institute, BDBC, School of Microelectronics, Beihang University, Beijing, People's Republic of China. Centre de Nanosciences et de Nanotechnologies, Université Paris-Sud, Université Paris-Saclay, 91120 Palaiseau, France
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12
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Fernández-Pacheco A, Vedmedenko E, Ummelen F, Mansell R, Petit D, Cowburn RP. Symmetry-breaking interlayer Dzyaloshinskii-Moriya interactions in synthetic antiferromagnets. NATURE MATERIALS 2019; 18:679-684. [PMID: 31160802 DOI: 10.1038/s41563-019-0386-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 04/18/2019] [Indexed: 05/12/2023]
Abstract
The magnetic interfacial Dzyaloshinskii-Moriya interaction (DMI) in multilayered thin films can lead to chiral spin states, which are of paramount importance for future spintronic technologies1,2. Interfacial DMI typically manifests as an intralayer interaction, mediated via a paramagnetic heavy metal in systems lacking inversion symmetry3. Here we show that, by designing synthetic antiferromagnets with canted magnetization states4,5, it is also possible to observe direct evidence of the interfacial interlayer DMI at room temperature. The interlayer DMI breaks the symmetry of the magnetic reversal process via the emergence of non-collinear spin states, which results in chiral exchange-biased hysteresis loops. The spin chiral interlayer interactions reported here are expected to manifest in a range of multilayered thin-film systems, opening up as yet unexplored avenues for the development and exploitation of chiral effects in magnetic heterostructures6-8.
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Affiliation(s)
- Amalio Fernández-Pacheco
- SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, UK.
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Elena Vedmedenko
- Institute of Applied Physics, University of Hamburg, Hamburg, Germany.
| | - Fanny Ummelen
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- Technical University of Eindhoven, Eindhoven, the Netherlands
| | - Rhodri Mansell
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- Department of Applied Physics, Aalto University School of Science, Aalto, Finland
| | - Dorothée Petit
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
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13
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Kim DH, Haruta M, Ko HW, Go G, Park HJ, Nishimura T, Kim DY, Okuno T, Hirata Y, Futakawa Y, Yoshikawa H, Ham W, Kim S, Kurata H, Tsukamoto A, Shiota Y, Moriyama T, Choe SB, Lee KJ, Ono T. Bulk Dzyaloshinskii-Moriya interaction in amorphous ferrimagnetic alloys. NATURE MATERIALS 2019; 18:685-690. [PMID: 31133731 DOI: 10.1038/s41563-019-0380-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 04/16/2019] [Indexed: 06/09/2023]
Abstract
Symmetry breaking is a fundamental concept that prevails in many branches of physics1-5. In magnetic materials, broken inversion symmetry induces the Dzyaloshinskii-Moriya interaction (DMI), which results in fascinating physical behaviours6-14 with the potential for application in future spintronic devices15-17. Here, we report the observation of a bulk DMI in GdFeCo amorphous ferrimagnets. The DMI is found to increase linearly with an increasing thickness of the ferrimagnetic layer, which is a clear signature of the bulk nature of DMI. We also found that the DMI is independent of the interface between the heavy metal and ferrimagnetic layer. This bulk DMI is attributed to an asymmetric distribution of the elemental content in the GdFeCo layer, with spatial inversion symmetry broken throughout the layer. We expect that our experimental identification of a bulk DMI will open up additional possibilities to exploit this interaction in a wide range of materials.
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Affiliation(s)
- Duck-Ho Kim
- Institute for Chemical Research, Kyoto University, Kyoto, Japan.
| | | | - Hye-Won Ko
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea
| | - Gyungchoon Go
- Department of Materials Science & Engineering, Korea University, Seoul, Republic of Korea
| | - Hyeon-Jong Park
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea
| | - Tomoe Nishimura
- Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | - Dae-Yun Kim
- Department of Physics and Institute of Applied Physics, Seoul National University, Seoul, Republic of Korea
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, Republic of Korea
| | - Takaya Okuno
- Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | - Yuushou Hirata
- Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | - Yasuhiro Futakawa
- College of Science and Technology, Nihon University, Funabashi, Chiba, Japan
| | - Hiroki Yoshikawa
- College of Science and Technology, Nihon University, Funabashi, Chiba, Japan
| | - Wooseung Ham
- Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | - Sanghoon Kim
- Institute for Chemical Research, Kyoto University, Kyoto, Japan
- Department of Physics, University of Ulsan, Ulsan, Republic of Korea
| | - Hiroki Kurata
- Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | - Arata Tsukamoto
- College of Science and Technology, Nihon University, Funabashi, Chiba, Japan
| | - Yoichi Shiota
- Institute for Chemical Research, Kyoto University, Kyoto, Japan
| | | | - Sug-Bong Choe
- Department of Physics and Institute of Applied Physics, Seoul National University, Seoul, Republic of Korea
| | - Kyung-Jin Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea
- Department of Materials Science & Engineering, Korea University, Seoul, Republic of Korea
| | - Teruo Ono
- Institute for Chemical Research, Kyoto University, Kyoto, Japan.
- Center for Spintronics Research Network (CSRN), Graduate School of Engineering Science, Osaka University, Osaka, Japan.
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14
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Koyama T, Nakatani Y, Ieda J, Chiba D. Electric field control of magnetic domain wall motion via modulation of the Dzyaloshinskii-Moriya interaction. SCIENCE ADVANCES 2018; 4:eaav0265. [PMID: 30588494 PMCID: PMC6303118 DOI: 10.1126/sciadv.aav0265] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 11/20/2018] [Indexed: 06/01/2023]
Abstract
We show that the electric field (EF) can control the domain wall (DW) velocity in a Pt/Co/Pd asymmetric structure. With the application of a gate voltage, a substantial change in DW velocity up to 50 m/s is observed, which is much greater than that observed in previous studies. Moreover, modulation of a DW velocity exceeding 100 m/s is demonstrated in this study. An EF-induced change in the interfacial Dzyaloshinskii-Moriya interaction (DMI) up to several percent is found to be the origin of the velocity modulation. The DMI-mediated velocity change shown here is a fundamentally different mechanism from that caused by EF-induced anisotropy modulation. Our results will pave the way for the electrical manipulation of spin structures and dynamics via DMI control, which can enhance the performance of spintronic devices.
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Affiliation(s)
- Tomohiro Koyama
- Department of Applied Physics, The University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
| | | | - Jun’ichi Ieda
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan
| | - Daichi Chiba
- Department of Applied Physics, The University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
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15
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Je SG, Vallobra P, Srivastava T, Rojas-Sánchez JC, Pham TH, Hehn M, Malinowski G, Baraduc C, Auffret S, Gaudin G, Mangin S, Béa H, Boulle O. Creation of Magnetic Skyrmion Bubble Lattices by Ultrafast Laser in Ultrathin Films. NANO LETTERS 2018; 18:7362-7371. [PMID: 30295499 DOI: 10.1021/acs.nanolett.8b03653] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Magnetic skyrmions are topologically nontrivial spin textures which hold great promise as stable information carriers in spintronic devices at the nanoscale. One of the major challenges for developing novel skyrmion-based memory and logic devices is fast and controlled creation of magnetic skyrmions at ambient conditions. Here we demonstrate controlled generation of skyrmion bubbles and skyrmion bubble lattices from a ferromagnetic state in sputtered ultrathin magnetic films at room temperature by a single ultrafast (35 fs) laser pulse. The skyrmion bubble density increases with the laser fluence, and it finally becomes saturated, forming disordered hexagonal lattices. Moreover, we present that the skyrmion bubble lattice configuration leads to enhanced topological stability as compared to isolated skyrmions, suggesting its promising use in data storage. Our findings shed light on the optical approach to the skyrmion bubble lattice in commonly accessible materials, paving the road toward the emerging skyrmion-based memory and synaptic devices.
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Affiliation(s)
- Soong-Geun Je
- INAC-SPINTEC, CNRS, CEA, Grenoble INP , Université Grenoble Alpes , 38000 Grenoble , France
- Institut Jean Lamour, CNRS UMR 7198 , Université de Lorraine , Nancy F-54500 , France
| | - Pierre Vallobra
- Institut Jean Lamour, CNRS UMR 7198 , Université de Lorraine , Nancy F-54500 , France
| | - Titiksha Srivastava
- INAC-SPINTEC, CNRS, CEA, Grenoble INP , Université Grenoble Alpes , 38000 Grenoble , France
| | | | - Thai Ha Pham
- Institut Jean Lamour, CNRS UMR 7198 , Université de Lorraine , Nancy F-54500 , France
| | - Michel Hehn
- Institut Jean Lamour, CNRS UMR 7198 , Université de Lorraine , Nancy F-54500 , France
| | - Gregory Malinowski
- Institut Jean Lamour, CNRS UMR 7198 , Université de Lorraine , Nancy F-54500 , France
| | - Claire Baraduc
- INAC-SPINTEC, CNRS, CEA, Grenoble INP , Université Grenoble Alpes , 38000 Grenoble , France
| | - Stéphane Auffret
- INAC-SPINTEC, CNRS, CEA, Grenoble INP , Université Grenoble Alpes , 38000 Grenoble , France
| | - Gilles Gaudin
- INAC-SPINTEC, CNRS, CEA, Grenoble INP , Université Grenoble Alpes , 38000 Grenoble , France
| | - Stéphane Mangin
- Institut Jean Lamour, CNRS UMR 7198 , Université de Lorraine , Nancy F-54500 , France
| | - Hélène Béa
- INAC-SPINTEC, CNRS, CEA, Grenoble INP , Université Grenoble Alpes , 38000 Grenoble , France
| | - Olivier Boulle
- INAC-SPINTEC, CNRS, CEA, Grenoble INP , Université Grenoble Alpes , 38000 Grenoble , France
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16
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Controlling Dzyaloshinskii-Moriya Interaction via Chirality Dependent Atomic-Layer Stacking, Insulator Capping and Electric Field. Sci Rep 2018; 8:12356. [PMID: 30120368 PMCID: PMC6097993 DOI: 10.1038/s41598-018-30063-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 07/19/2018] [Indexed: 11/08/2022] Open
Abstract
Using first-principles calculations, we demonstrate several approaches to control Dzyaloshinskii-Moriya Interaction (DMI) in ultrathin films with perpendicular magnetic anisotropy. First, we find that DMI is significantly enhanced when the ferromagnetic (FM) layer is sandwiched between nonmagnetic (NM) layers inducing additive DMI in NM1/FM/NM2 structures. For instance, when two NM layers are chosen to induce DMI of opposite chirality in Co, e.g. NM1 representing Au, Ir, Al or Pb, and NM2 being Pt, the resulting DMI in NM1/Co/Pt trilayers is enhanced compared to Co/Pt bilayers. Moreover, DMI can be significantly enhanced further in case of using FM layer comprising Fe and Co layers. Namely, it is found that the DMI in Ir/Fe/Co/Pt structure can be enhanced by 80% compared to that of Co/Pt bilayers reaching a very large DMI amplitude of 5.59 meV/atom. Our second approach for enhancing DMI is to use oxide capping layer. We show that DMI is enhanced by 60% in Oxide/Co/Pt structures compared to Co/Pt bilayers. Moreover, we unveiled the DMI mechanism at Oxide/Co interface due to Rashba effect, which is different to Fert-Levy DMI at FM/NM interfaces. Finally, we demonstrate that DMI amplitude can be modulated using an electric field with an efficiency factor comparable to that of the electric field control of perpendicular magnetic anisotropy in transition metal/oxide interfaces. These approaches of DMI controlling pave the way for skyrmion and domain wall motion-based spintronic applications.
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17
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Srivastava T, Schott M, Juge R, Křižáková V, Belmeguenai M, Roussigné Y, Bernand-Mantel A, Ranno L, Pizzini S, Chérif SM, Stashkevich A, Auffret S, Boulle O, Gaudin G, Chshiev M, Baraduc C, Béa H. Large-Voltage Tuning of Dzyaloshinskii-Moriya Interactions: A Route toward Dynamic Control of Skyrmion Chirality. NANO LETTERS 2018; 18:4871-4877. [PMID: 29924621 DOI: 10.1021/acs.nanolett.8b01502] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Electric control of magnetism is a prerequisite for efficient and low-power spintronic devices. More specifically, in heavy metal-ferromagnet-insulator heterostructures, voltage gating has been shown to locally and dynamically tune magnetic properties such as interface anisotropy and saturation magnetization. However, its effect on interfacial Dzyaloshinskii-Moriya Interaction (DMI), which is crucial for the stability of magnetic skyrmions, has been challenging to achieve and has not been reported yet for ultrathin films. Here, we demonstrate a 130% variation of DMI with electric field in Ta/FeCoB/TaO x trilayer through Brillouin Light Spectroscopy (BLS). Using polar magneto-optical Kerr-effect microscopy, we further show a monotonic variation of DMI and skyrmionic bubble size with electric field with an unprecedented efficiency. We anticipate through our observations that a sign reversal of DMI with an electric field is possible, leading to a chirality switch. This dynamic manipulation of DMI establishes an additional degree of control to engineer programmable skyrmion-based memory or logic devices.
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Affiliation(s)
- Titiksha Srivastava
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec , 38000 Grenoble , France
| | - Marine Schott
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec , 38000 Grenoble , France
| | - Roméo Juge
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec , 38000 Grenoble , France
| | - Viola Křižáková
- Univ. Grenoble Alpes, CNRS, Institut Néel , F-38042 Grenoble , France
| | - Mohamed Belmeguenai
- Laboratoire des Sciences des Procédés et des Matériaux , Université Paris 13 Nord , 93430 Villetaneuse , France
| | - Yves Roussigné
- Laboratoire des Sciences des Procédés et des Matériaux , Université Paris 13 Nord , 93430 Villetaneuse , France
| | | | - Laurent Ranno
- Univ. Grenoble Alpes, CNRS, Institut Néel , F-38042 Grenoble , France
| | - Stefania Pizzini
- Univ. Grenoble Alpes, CNRS, Institut Néel , F-38042 Grenoble , France
| | - Salim-Mourad Chérif
- Laboratoire des Sciences des Procédés et des Matériaux , Université Paris 13 Nord , 93430 Villetaneuse , France
| | - Andrey Stashkevich
- Laboratoire des Sciences des Procédés et des Matériaux , Université Paris 13 Nord , 93430 Villetaneuse , France
| | - Stéphane Auffret
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec , 38000 Grenoble , France
| | - Olivier Boulle
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec , 38000 Grenoble , France
| | - Gilles Gaudin
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec , 38000 Grenoble , France
| | - Mairbek Chshiev
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec , 38000 Grenoble , France
| | - Claire Baraduc
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec , 38000 Grenoble , France
| | - Hélène Béa
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec , 38000 Grenoble , France
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18
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Lee JM, Cai K, Yang G, Liu Y, Ramaswamy R, He P, Yang H. Field-Free Spin-Orbit Torque Switching from Geometrical Domain-Wall Pinning. NANO LETTERS 2018; 18:4669-4674. [PMID: 29953239 DOI: 10.1021/acs.nanolett.8b00773] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Spin-orbit torques, which utilize spin currents arising from the spin-orbit coupling, offer a novel method for the electrical switching of the magnetization with perpendicular anisotropy. However, the necessity of an external magnetic field to achieve deterministic switching is an obstacle for realizing practical spin-orbit torque devices with all-electric operation. Here, we report field-free spin-orbit torque switching by exploiting the domain-wall motion in an anti-notched microwire with perpendicular anisotropy, which exhibits multidomain states stabilized by the domain-wall surface tension. The combination of spin-orbit torque, Dzyaloshinskii-Moriya interactions, and domain-wall surface-tension-induced geometrical pinning allows the deterministic control of the domain wall and offers a novel method to achieve a field-free spin-orbit torque switching. Our work demonstrates the proof of concept of a perpendicular memory cell that can be readily adopted in three-terminal magnetic memory.
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Affiliation(s)
- Jong Min Lee
- Department of Electrical and Computer Engineering , National University of Singapore , 117576 Singapore
| | - Kaiming Cai
- Department of Electrical and Computer Engineering , National University of Singapore , 117576 Singapore
| | - Guang Yang
- Department of Electrical and Computer Engineering , National University of Singapore , 117576 Singapore
| | - Yang Liu
- Department of Electrical and Computer Engineering , National University of Singapore , 117576 Singapore
| | - Rajagopalan Ramaswamy
- Department of Electrical and Computer Engineering , National University of Singapore , 117576 Singapore
| | - Pan He
- Department of Electrical and Computer Engineering , National University of Singapore , 117576 Singapore
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering , National University of Singapore , 117576 Singapore
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19
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Dovzhenko Y, Casola F, Schlotter S, Zhou TX, Büttner F, Walsworth RL, Beach GSD, Yacoby A. Magnetostatic twists in room-temperature skyrmions explored by nitrogen-vacancy center spin texture reconstruction. Nat Commun 2018; 9:2712. [PMID: 30006532 PMCID: PMC6045603 DOI: 10.1038/s41467-018-05158-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 05/01/2018] [Indexed: 11/27/2022] Open
Abstract
Magnetic skyrmions are two-dimensional non-collinear spin textures characterized by an integer topological number. Room-temperature skyrmions were recently found in magnetic multilayer stacks, where their stability was largely attributed to the interfacial Dzyaloshinskii-Moriya interaction. The strength of this interaction and its role in stabilizing the skyrmions is not yet well understood, and imaging of the full spin structure is needed to address this question. Here, we use a nitrogen-vacancy centre in diamond to measure a map of magnetic fields produced by a skyrmion in a magnetic multilayer under ambient conditions. We compute the manifold of candidate spin structures and select the physically meaningful solution. We find a Néel-type skyrmion whose chirality is not left-handed, contrary to preceding reports. We propose skyrmion tube-like structures whose chirality rotates through the film thickness. We show that NV magnetometry, combined with our analysis method, provides a unique tool to investigate this previously inaccessible phenomenon.
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Affiliation(s)
- Y Dovzhenko
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA, 02138, USA
| | - F Casola
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA, 02138, USA
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, 02138, USA
| | - S Schlotter
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - T X Zhou
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA, 02138, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - F Büttner
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - R L Walsworth
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA, 02138, USA
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, 02138, USA
| | - G S D Beach
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - A Yacoby
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA, 02138, USA.
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20
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Legrand W, Chauleau JY, Maccariello D, Reyren N, Collin S, Bouzehouane K, Jaouen N, Cros V, Fert A. Hybrid chiral domain walls and skyrmions in magnetic multilayers. SCIENCE ADVANCES 2018; 4:eaat0415. [PMID: 30035224 PMCID: PMC6054507 DOI: 10.1126/sciadv.aat0415] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 06/11/2018] [Indexed: 05/24/2023]
Abstract
Noncollinear spin textures in ferromagnetic ultrathin films are currently the subject of renewed interest since the discovery of the interfacial Dzyaloshinskii-Moriya interaction (DMI). This antisymmetric exchange interaction selects a given chirality for the spin textures and allows stabilizing configurations with nontrivial topology including chiral domain walls (DWs) and magnetic skyrmions. Moreover, it has many crucial consequences on the dynamical properties of these topological structures. In recent years, the study of noncollinear spin textures has been extended from single ultrathin layers to magnetic multilayers with broken inversion symmetry. This extension of the structures in the vertical dimension allows room temperature stability and very efficient current-induced motion for both Néel DWs and skyrmions. We show how, in these multilayered systems, the interlayer interactions can actually lead to hybrid chiral magnetization arrangements. The described thickness-dependent reorientation of DWs is experimentally confirmed by studying demagnetized multilayers through circular dichroism in x-ray resonant magnetic scattering. We also demonstrate a simple yet reliable method for determining the magnitude of the DMI from static domain measurements even in the presence of these hybrid chiral structures by taking into account the actual profile of the DWs. The existence of these novel hybrid chiral textures has far-reaching implications on how to stabilize and manipulate DWs, as well as skymionic structures in magnetic multilayers.
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Affiliation(s)
- William Legrand
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Jean-Yves Chauleau
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
- Synchrotron SOLEIL, L’Orme des Merisiers, Gif-sur-Yvette 91192, France
| | - Davide Maccariello
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Nicolas Reyren
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Sophie Collin
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Karim Bouzehouane
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Nicolas Jaouen
- Synchrotron SOLEIL, L’Orme des Merisiers, Gif-sur-Yvette 91192, France
| | - Vincent Cros
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - Albert Fert
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
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21
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Kim S, Ueda K, Go G, Jang PH, Lee KJ, Belabbes A, Manchon A, Suzuki M, Kotani Y, Nakamura T, Nakamura K, Koyama T, Chiba D, Yamada KT, Kim DH, Moriyama T, Kim KJ, Ono T. Correlation of the Dzyaloshinskii-Moriya interaction with Heisenberg exchange and orbital asphericity. Nat Commun 2018; 9:1648. [PMID: 29695776 PMCID: PMC5916936 DOI: 10.1038/s41467-018-04017-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 03/27/2018] [Indexed: 11/09/2022] Open
Abstract
Chiral spin textures of a ferromagnetic layer in contact to a heavy non-magnetic metal, such as Néel-type domain walls and skyrmions, have been studied intensively because of their potential for future nanomagnetic devices. The Dyzaloshinskii-Moriya interaction (DMI) is an essential phenomenon for the formation of such chiral spin textures. In spite of recent theoretical progress aiming at understanding the microscopic origin of the DMI, an experimental investigation unravelling the physics at stake is still required. Here we experimentally demonstrate the close correlation of the DMI with the anisotropy of the orbital magnetic moment and with the magnetic dipole moment of the ferromagnetic metal in addition to Heisenberg exchange. The density functional theory and the tight-binding model calculations reveal that inversion symmetry breaking with spin-orbit coupling gives rise to the orbital-related correlation. Our study provides the experimental connection between the orbital physics and the spin-orbit-related phenomena, such as DMI.
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Affiliation(s)
- Sanghoon Kim
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan. .,Department of Physics, University of Ulsan, Ulsan, 44610, Korea.
| | - Kohei Ueda
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan.,Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Gyungchoon Go
- Department of Materials Science & Engineering, Korea University, Seoul, 02841, Korea
| | - Peong-Hwa Jang
- Department of Materials Science & Engineering, Korea University, Seoul, 02841, Korea
| | - Kyung-Jin Lee
- Department of Materials Science & Engineering, Korea University, Seoul, 02841, Korea.,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Korea
| | - Abderrezak Belabbes
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Aurelien Manchon
- Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Motohiro Suzuki
- Japan Synchrotron Radiation Research Institute (JASRI), Sayo, Hyogo, 679-5198, Japan
| | - Yoshinori Kotani
- Japan Synchrotron Radiation Research Institute (JASRI), Sayo, Hyogo, 679-5198, Japan
| | - Tetsuya Nakamura
- Japan Synchrotron Radiation Research Institute (JASRI), Sayo, Hyogo, 679-5198, Japan
| | - Kohji Nakamura
- Department of Physics Engineering, Mie University, Tsu, Mie, 514-8507, Japan
| | - Tomohiro Koyama
- Department of Applied Physics, The University of Tokyo, Bunkyo, Tokyo, 113-8656, Japan
| | - Daichi Chiba
- Department of Applied Physics, The University of Tokyo, Bunkyo, Tokyo, 113-8656, Japan
| | - Kihiro T Yamada
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Duck-Ho Kim
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Takahiro Moriyama
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Kab-Jin Kim
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan.,Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Korea
| | - Teruo Ono
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan. .,Center for Spintronics Research Network (CSRN), Graduate School of Engineering Science, Osaka University, Osaka, 560-8531, Japan.
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22
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Yang W, Yang H, Cao Y, Yan P. Photonic orbital angular momentum transfer and magnetic skyrmion rotation. OPTICS EXPRESS 2018; 26:8778-8790. [PMID: 29715841 DOI: 10.1364/oe.26.008778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 03/19/2018] [Indexed: 06/08/2023]
Abstract
Magnetic skyrmions are chiral quasiparticles that show promise for future spintronic applications such as skyrmion racetrack memories and logic devices because of their topological stability, small size (typically ∼ 3 - 500 nm), and ultralow threshold force to drive their motion. On the other hand, the ability of light to carry and deliver orbital angular momentum (OAM) in the form of optical vortices has attracted a lot of interest. In this work, we predict a photonic OAM transfer effect, by studying the dynamics of magnetic skyrmions subject to Laguerre-Gaussian optical vortices, which manifests a rotational motion of the skyrmionic quasiparticle around the beam axis. The topological charge of the optical vortex determines both the magnitude and the handedness of the rotation velocity of skyrmions. In our proposal, the twisted light beam acts as an optical tweezer to enable us displacing skyrmions over large-scale defects in magnetic films to avoid being captured.
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23
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Gweon HK, Yun SJ, Lim SH. A very large perpendicular magnetic anisotropy in Pt/Co/MgO trilayers fabricated by controlling the MgO sputtering power and its thickness. Sci Rep 2018; 8:1266. [PMID: 29352244 PMCID: PMC5775398 DOI: 10.1038/s41598-018-19656-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 01/05/2018] [Indexed: 11/09/2022] Open
Abstract
The perpendicular magnetic anisotropy (PMA) properties of Pt/Co/MgO trilayers are investigated as a function of the MgO sputtering power (PMgO) and its thickness (tMgO), both of which are important parameters affecting the degree of oxygen interpenetration into Co during sputtering. A strong PMA is achieved at small values of PMgO and tMgO, where the oxygen interpenetration into Co is expected to be small. The range of oxygen interpenetration is relatively extended in such a way that it affects both the Pt/Co and Co/MgO interfaces. The PMA properties of as-deposited samples are improved by post-annealing for temperatures up to 400 °C examined in this study, probably due to the diffusion of the interpenetrated oxygen atoms toward the Co/MgO interface. In a structure of Pt/Co (0.6 nm)/MgO (2 nm), which is fabricated at PMgO = 50 W and then annealed at 400 °C, a huge saturation field is achieved (over 40 kOe) indicating a very strong PMA. Between the two interfaces of Pt/Co and Co/MgO, the PMA is mainly due to the former in the as-deposited state, but the contribution of the latter increases with the increase in the annealing temperature.
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Affiliation(s)
- Hyung Keun Gweon
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, Korea
| | - Seok Jin Yun
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, Korea
| | - Sang Ho Lim
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, Korea.
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24
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Baumgartner M, Garello K, Mendil J, Avci CO, Grimaldi E, Murer C, Feng J, Gabureac M, Stamm C, Acremann Y, Finizio S, Wintz S, Raabe J, Gambardella P. Spatially and time-resolved magnetization dynamics driven by spin-orbit torques. NATURE NANOTECHNOLOGY 2017; 12:980-986. [PMID: 28825713 DOI: 10.1038/nnano.2017.151] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 06/28/2017] [Indexed: 06/07/2023]
Abstract
Current-induced spin-orbit torques are one of the most effective ways to manipulate the magnetization in spintronic devices, and hold promise for fast switching applications in non-volatile memory and logic units. Here, we report the direct observation of spin-orbit-torque-driven magnetization dynamics in Pt/Co/AlOx dots during current pulse injection. Time-resolved X-ray images with 25 nm spatial and 100 ps temporal resolution reveal that switching is achieved within the duration of a subnanosecond current pulse by the fast nucleation of an inverted domain at the edge of the dot and propagation of a tilted domain wall across the dot. The nucleation point is deterministic and alternates between the four dot quadrants depending on the sign of the magnetization, current and external field. Our measurements reveal how the magnetic symmetry is broken by the concerted action of the damping-like and field-like spin-orbit torques and the Dzyaloshinskii-Moriya interaction, and show that reproducible switching events can be obtained for over 1012 reversal cycles.
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Affiliation(s)
| | - Kevin Garello
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
- IMEC, Kapeldreef 75, 3001 Leuven, Belgium
| | - Johannes Mendil
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Can Onur Avci
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Eva Grimaldi
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Christoph Murer
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Junxiao Feng
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Mihai Gabureac
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Christian Stamm
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Yves Acremann
- Laboratory for Solid State Physics, ETH Zürich, 8093 Zürich, Switzerland
| | | | | | - Jörg Raabe
- Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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25
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Schott M, Bernand-Mantel A, Ranno L, Pizzini S, Vogel J, Béa H, Baraduc C, Auffret S, Gaudin G, Givord D. The Skyrmion Switch: Turning Magnetic Skyrmion Bubbles on and off with an Electric Field. NANO LETTERS 2017; 17:3006-3012. [PMID: 28437086 DOI: 10.1021/acs.nanolett.7b00328] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nanoscale magnetic skyrmions are considered as potential information carriers for future spintronics memory and logic devices. Such applications will require the control of their local creation and annihilation, which involves so far solutions that are either energy consuming or difficult to integrate. Here we demonstrate the control of skyrmion bubbles nucleation and annihilation using electric field gating, an easily integrable and potentially energetically efficient solution. We present a detailed stability diagram of the skyrmion bubbles in a Pt/Co/oxide trilayer and show that their stability can be controlled via an applied electric field. An analytical bubble model with the Dzyaloshinskii-Moriya interaction imbedded in the domain wall energy accounts for the observed electrical skyrmion switching effect. This allows us to unveil the origin of the electrical control of skyrmions stability and to show that both magnetic dipolar interaction and the Dzyaloshinskii-Moriya interaction play an important role in the skyrmion bubble stabilization.
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Affiliation(s)
- Marine Schott
- Université Grenoble Alpes , F-38000 Grenoble, France
- CNRS, Institut NEEL , F-38000 Grenoble, France
- CNRS, SPINTEC , F-38000 Grenoble, France
- CEA, INAC-SPINTEC , F-38000 Grenoble, France
| | - Anne Bernand-Mantel
- Université Grenoble Alpes , F-38000 Grenoble, France
- CNRS, Institut NEEL , F-38000 Grenoble, France
| | - Laurent Ranno
- Université Grenoble Alpes , F-38000 Grenoble, France
- CNRS, Institut NEEL , F-38000 Grenoble, France
| | - Stefania Pizzini
- Université Grenoble Alpes , F-38000 Grenoble, France
- CNRS, Institut NEEL , F-38000 Grenoble, France
| | - Jan Vogel
- Université Grenoble Alpes , F-38000 Grenoble, France
- CNRS, Institut NEEL , F-38000 Grenoble, France
| | - Hélène Béa
- Université Grenoble Alpes , F-38000 Grenoble, France
- CNRS, SPINTEC , F-38000 Grenoble, France
- CEA, INAC-SPINTEC , F-38000 Grenoble, France
| | - Claire Baraduc
- Université Grenoble Alpes , F-38000 Grenoble, France
- CNRS, SPINTEC , F-38000 Grenoble, France
- CEA, INAC-SPINTEC , F-38000 Grenoble, France
| | - Stéphane Auffret
- Université Grenoble Alpes , F-38000 Grenoble, France
- CNRS, SPINTEC , F-38000 Grenoble, France
- CEA, INAC-SPINTEC , F-38000 Grenoble, France
| | - Gilles Gaudin
- Université Grenoble Alpes , F-38000 Grenoble, France
- CNRS, SPINTEC , F-38000 Grenoble, France
- CEA, INAC-SPINTEC , F-38000 Grenoble, France
| | - Dominique Givord
- Université Grenoble Alpes , F-38000 Grenoble, France
- CNRS, Institut NEEL , F-38000 Grenoble, France
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26
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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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27
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Wide-Range Probing of Dzyaloshinskii-Moriya Interaction. Sci Rep 2017; 7:45498. [PMID: 28361907 PMCID: PMC5374437 DOI: 10.1038/srep45498] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 02/28/2017] [Indexed: 11/08/2022] Open
Abstract
The Dzyaloshinskii-Moriya interaction (DMI) in magnetic objects is of enormous interest, because it generates built-in chirality of magnetic domain walls (DWs) and topologically protected skyrmions, leading to efficient motion driven by spin-orbit torques. Because of its importance for both potential applications and fundamental research, many experimental efforts have been devoted to DMI investigation. However, current experimental probing techniques cover only limited ranges of the DMI strength and have specific sample requirements. Thus, there are no versatile methods to quantify DMI over a wide range of values. Here, we present such an experimental scheme, which is based on the angular dependence of asymmetric DW motion. This method can be used to determine values of DMI much larger than the maximum strength of the external magnetic field strength, which demonstrates that various DMI strengths can be quantified with a single measurement setup. This scheme may thus prove essential to DMI-related emerging fields in nanotechnology.
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28
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Yu G, Upadhyaya P, Shao Q, Wu H, Yin G, Li X, He C, Jiang W, Han X, Amiri PK, Wang KL. Room-Temperature Skyrmion Shift Device for Memory Application. NANO LETTERS 2017; 17:261-268. [PMID: 27966987 DOI: 10.1021/acs.nanolett.6b04010] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Magnetic skyrmions are intensively explored for potential applications in ultralow-energy data storage and computing. To create practical skyrmionic memory devices, it is necessary to electrically create and manipulate these topologically protected information carriers in thin films, thus realizing both writing and addressing functions. Although room-temperature skyrmions have been previously observed, fully electrically controllable skyrmionic memory devices, integrating both of these functions, have not been developed to date. Here, we demonstrate a room-temperature skyrmion shift memory device, where individual skyrmions are controllably generated and shifted using current-induced spin-orbit torques. Particularly, it is shown that one can select the device operation mode in between (i) writing new single skyrmions or (ii) shifting existing skyrmions by controlling the magnitude and duration of current pulses. Thus, we electrically realize both writing and addressing of a stream of skyrmions in the device. This prototype demonstration brings skyrmions closer to real-world computing applications.
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Affiliation(s)
- Guoqiang Yu
- Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States
| | - Pramey Upadhyaya
- Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States
| | - Qiming Shao
- Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States
| | - Hao Wu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Gen Yin
- Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States
| | - Xiang Li
- Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States
| | | | - Wanjun Jiang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University , Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter , Beijing 100084, China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100190, China
| | - Pedram Khalili Amiri
- Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States
| | - Kang L Wang
- Department of Electrical Engineering, University of California , Los Angeles, California 90095, United States
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29
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Siracusano G, Tomasello R, Giordano A, Puliafito V, Azzerboni B, Ozatay O, Carpentieri M, Finocchio G. Magnetic Radial Vortex Stabilization and Efficient Manipulation Driven by the Dzyaloshinskii-Moriya Interaction and Spin-Transfer Torque. PHYSICAL REVIEW LETTERS 2016; 117:087204. [PMID: 27588879 DOI: 10.1103/physrevlett.117.087204] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Indexed: 06/06/2023]
Abstract
Solitons are very promising for the design of the next generation of ultralow power devices for storage and computation. The key ingredient to achieving this goal is the fundamental understanding of their stabilization and manipulation. Here, we show how the interfacial Dzyaloshinskii-Moriya Interaction (IDMI) is able to lift the energy degeneracy of a magnetic vortex state by stabilizing a topological soliton with radial chirality, hereafter called radial vortex. It has a noninteger Skyrmion number S (0.5<|S|<1) due to both the vortex core polarity and the magnetization tilting induced by the IDMI boundary conditions. Micromagnetic simulations predict that a magnetoresistive memory based on the radial vortex state in both free and polarizer layers can be efficiently switched by a threshold current density smaller than 10^{6} A/cm^{2}. The switching processes occur via the nucleation of topologically connected vortices and vortex-antivortex pairs, followed by spin-wave emissions due to vortex-antivortex annihilations.
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Affiliation(s)
- G Siracusano
- Department of Mathematical and Computer Sciences, Physical Sciences and Earth Sciences, University of Messina, I-98166 Messina, Italy
| | - R Tomasello
- Department of Engineering, Polo Scientifico Didattico di Terni, University of Perugia, I-50100 Terni, Italy
| | - A Giordano
- Department of Mathematical and Computer Sciences, Physical Sciences and Earth Sciences, University of Messina, I-98166 Messina, Italy
| | - V Puliafito
- Department of Engineering, University of Messina, I-98166 Messina, Italy
| | - B Azzerboni
- Department of Engineering, University of Messina, I-98166 Messina, Italy
| | - O Ozatay
- Department of Physics, Bogazici University, 34342 Bebek/Istanbul, Turkey
| | - M Carpentieri
- Department of Electrical and Information Engineering, Politecnico di Bari, via E. Orabona 4, I-70125 Bari, Italy
| | - G Finocchio
- Department of Mathematical and Computer Sciences, Physical Sciences and Earth Sciences, University of Messina, I-98166 Messina, Italy
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30
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Han DS, Kim NH, Kim JS, Yin Y, Koo JW, Cho J, Lee S, Kläui M, Swagten HJM, Koopmans B, You CY. Asymmetric Hysteresis for Probing Dzyaloshinskii-Moriya Interaction. NANO LETTERS 2016; 16:4438-4446. [PMID: 27348607 DOI: 10.1021/acs.nanolett.6b01593] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The interfacial Dzyaloshinskii-Moriya interaction (DMI) is intimately related to the prospect of superior domain-wall dynamics and the formation of magnetic skyrmions. Although some experimental efforts have been recently proposed to quantify these interactions and the underlying physics, it is still far from trivial to address the interfacial DMI. Inspired by the reported tilt of the magnetization of the side edge of a thin film structure, we here present a quasi-static, straightforward measurement tool. By using laterally asymmetric triangular-shaped microstructures, it is demonstrated that interfacial DMI combined with an in-plane magnetic field yields a unique and significant shift in magnetic hysteresis. By systematic variation of the shape of the triangular objects combined with a droplet model for domain nucleation, a robust value for the strength and sign of interfacial DMI is obtained. This method gives immediate and quantitative access to DMI, enabling a much faster exploration of new DMI systems for future nanotechnology.
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Affiliation(s)
- Dong-Soo Han
- Department of Applied Physics, Center for NanoMaterials, Eindhoven University of Technology , PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - Nam-Hui Kim
- Department of Physics, Inha University , Incheon 22212, Republic of Korea
- Institut of Physics and Graduate School of Excellence Materials Science in Mainz, Johannes Gutenberg-Universität Mainz , 55099 Mainz, Germany
| | - June-Seo Kim
- Department of Applied Physics, Center for NanoMaterials, Eindhoven University of Technology , PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - Yuxiang Yin
- Department of Applied Physics, Center for NanoMaterials, Eindhoven University of Technology , PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - Jung-Woo Koo
- Department of Applied Physics, Center for NanoMaterials, Eindhoven University of Technology , PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - Jaehun Cho
- Department of Physics, Inha University , Incheon 22212, Republic of Korea
| | - Sukmock Lee
- Department of Physics, Inha University , Incheon 22212, Republic of Korea
| | - Mathias Kläui
- Institut of Physics and Graduate School of Excellence Materials Science in Mainz, Johannes Gutenberg-Universität Mainz , 55099 Mainz, Germany
| | - Henk J M Swagten
- Department of Applied Physics, Center for NanoMaterials, Eindhoven University of Technology , PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - Bert Koopmans
- Department of Applied Physics, Center for NanoMaterials, Eindhoven University of Technology , PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - Chun-Yeol You
- Department of Physics, Inha University , Incheon 22212, Republic of Korea
- Department of Emerging Materials Science, DGIST , Daegu 42988, Republic of Korea
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31
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Boulle O, Vogel J, Yang H, Pizzini S, de Souza Chaves D, Locatelli A, Menteş TO, Sala A, Buda-Prejbeanu LD, Klein O, Belmeguenai M, Roussigné Y, Stashkevich A, Chérif SM, Aballe L, Foerster M, Chshiev M, Auffret S, Miron IM, Gaudin G. Room-temperature chiral magnetic skyrmions in ultrathin magnetic nanostructures. NATURE NANOTECHNOLOGY 2016; 11:449-454. [PMID: 26809057 DOI: 10.1038/nnano.2015.315] [Citation(s) in RCA: 226] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 12/01/2015] [Indexed: 06/05/2023]
Abstract
Magnetic skyrmions are chiral spin structures with a whirling configuration. Their topological properties, nanometre size and the fact that they can be moved by small current densities have opened a new paradigm for the manipulation of magnetization at the nanoscale. Chiral skyrmion structures have so far been experimentally demonstrated only in bulk materials and in epitaxial ultrathin films, and under an external magnetic field or at low temperature. Here, we report on the observation of stable skyrmions in sputtered ultrathin Pt/Co/MgO nanostructures at room temperature and zero external magnetic field. We use high lateral resolution X-ray magnetic circular dichroism microscopy to image their chiral Néel internal structure, which we explain as due to the large strength of the Dzyaloshinskii-Moriya interaction as revealed by spin wave spectroscopy measurements. Our results are substantiated by micromagnetic simulations and numerical models, which allow the identification of the physical mechanisms governing the size and stability of the skyrmions.
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Affiliation(s)
- Olivier Boulle
- Univ. Grenoble Alpes, SPINTEC, Grenoble F-38000, France
- CNRS, SPINTEC, Grenoble F-38000, France
- CEA, INAC-SPINTEC, Grenoble F-38000, France
| | - Jan Vogel
- CNRS, Institut Néel, 25 avenue des Martyrs, B.P. 166, Grenoble Cedex 9 38042, France
- Univ. Grenoble Alpes, Institut Néel, 25 avenue des Martyrs, B.P. 166, Grenoble Cedex 9 38042, France
| | - Hongxin Yang
- Univ. Grenoble Alpes, SPINTEC, Grenoble F-38000, France
- CNRS, SPINTEC, Grenoble F-38000, France
- CEA, INAC-SPINTEC, Grenoble F-38000, France
| | - Stefania Pizzini
- CNRS, Institut Néel, 25 avenue des Martyrs, B.P. 166, Grenoble Cedex 9 38042, France
- Univ. Grenoble Alpes, Institut Néel, 25 avenue des Martyrs, B.P. 166, Grenoble Cedex 9 38042, France
| | - Dayane de Souza Chaves
- CNRS, Institut Néel, 25 avenue des Martyrs, B.P. 166, Grenoble Cedex 9 38042, France
- Univ. Grenoble Alpes, Institut Néel, 25 avenue des Martyrs, B.P. 166, Grenoble Cedex 9 38042, France
| | - Andrea Locatelli
- Elettra-Sincrotrone, S.C.p.A, S.S 14 - km 163.5 in AREA Science Park 34149 Basovizza, Trieste, Italy
| | - Tevfik Onur Menteş
- Elettra-Sincrotrone, S.C.p.A, S.S 14 - km 163.5 in AREA Science Park 34149 Basovizza, Trieste, Italy
| | - Alessandro Sala
- Elettra-Sincrotrone, S.C.p.A, S.S 14 - km 163.5 in AREA Science Park 34149 Basovizza, Trieste, Italy
| | - Liliana D Buda-Prejbeanu
- Univ. Grenoble Alpes, SPINTEC, Grenoble F-38000, France
- CNRS, SPINTEC, Grenoble F-38000, France
- CEA, INAC-SPINTEC, Grenoble F-38000, France
| | - Olivier Klein
- Univ. Grenoble Alpes, SPINTEC, Grenoble F-38000, France
- CNRS, SPINTEC, Grenoble F-38000, France
- CEA, INAC-SPINTEC, Grenoble F-38000, France
| | - Mohamed Belmeguenai
- LSPM (CNRS-UPR 3407), Université Paris 13, Sorbonne Paris Cité, 99 avenue Jean-Baptiste Clément, Villetaneuse 93430, France
| | - Yves Roussigné
- LSPM (CNRS-UPR 3407), Université Paris 13, Sorbonne Paris Cité, 99 avenue Jean-Baptiste Clément, Villetaneuse 93430, France
| | - Andrey Stashkevich
- LSPM (CNRS-UPR 3407), Université Paris 13, Sorbonne Paris Cité, 99 avenue Jean-Baptiste Clément, Villetaneuse 93430, France
| | - Salim Mourad Chérif
- LSPM (CNRS-UPR 3407), Université Paris 13, Sorbonne Paris Cité, 99 avenue Jean-Baptiste Clément, Villetaneuse 93430, France
| | - Lucia Aballe
- ALBA Synchrotron Light Facility, Carretera BP 1413, Km. 3.3, Cerdanyola del Vallès, Barcelona 08290, Spain
| | - Michael Foerster
- ALBA Synchrotron Light Facility, Carretera BP 1413, Km. 3.3, Cerdanyola del Vallès, Barcelona 08290, Spain
| | - Mairbek Chshiev
- Univ. Grenoble Alpes, SPINTEC, Grenoble F-38000, France
- CNRS, SPINTEC, Grenoble F-38000, France
- CEA, INAC-SPINTEC, Grenoble F-38000, France
| | - Stéphane Auffret
- Univ. Grenoble Alpes, SPINTEC, Grenoble F-38000, France
- CNRS, SPINTEC, Grenoble F-38000, France
- CEA, INAC-SPINTEC, Grenoble F-38000, France
| | - Ioan Mihai Miron
- Univ. Grenoble Alpes, SPINTEC, Grenoble F-38000, France
- CNRS, SPINTEC, Grenoble F-38000, France
- CEA, INAC-SPINTEC, Grenoble F-38000, France
| | - Gilles Gaudin
- Univ. Grenoble Alpes, SPINTEC, Grenoble F-38000, France
- CNRS, SPINTEC, Grenoble F-38000, France
- CEA, INAC-SPINTEC, Grenoble F-38000, France
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32
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Moreau-Luchaire C, Mouta S C, Reyren N, Sampaio J, Vaz CAF, Van Horne N, Bouzehouane K, Garcia K, Deranlot C, Warnicke P, Wohlhüter P, George JM, Weigand M, Raabe J, Cros V, Fert A. Additive interfacial chiral interaction in multilayers for stabilization of small individual skyrmions at room temperature. NATURE NANOTECHNOLOGY 2016; 11:444-8. [PMID: 26780660 DOI: 10.1038/nnano.2015.313] [Citation(s) in RCA: 270] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/30/2015] [Indexed: 05/12/2023]
Abstract
Facing the ever-growing demand for data storage will most probably require a new paradigm. Nanoscale magnetic skyrmions are anticipated to solve this issue as they are arguably the smallest spin textures in magnetic thin films in nature. We designed cobalt-based multilayered thin films in which the cobalt layer is sandwiched between two heavy metals and so provides additive interfacial Dzyaloshinskii-Moriya interactions (DMIs), which reach a value close to 2 mJ m(-2) in the case of the Ir|Co|Pt asymmetric multilayers. Using a magnetization-sensitive scanning X-ray transmission microscopy technique, we imaged small magnetic domains at very low fields in these multilayers. The study of their behaviour in a perpendicular magnetic field allows us to conclude that they are actually magnetic skyrmions stabilized by the large DMI. This discovery of stable sub-100 nm individual skyrmions at room temperature in a technologically relevant material opens the way for device applications in the near future.
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Affiliation(s)
- C Moreau-Luchaire
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - C Mouta S
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
- School of Computer Science, University of Manchester, Manchester M13 9PL, UK
| | - N Reyren
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - J Sampaio
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - C A F Vaz
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - N Van Horne
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - K Bouzehouane
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - K Garcia
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - C Deranlot
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - P Warnicke
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - P Wohlhüter
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - J-M George
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - M Weigand
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - J Raabe
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - V Cros
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
| | - A Fert
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767, France
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33
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Woo S, Litzius K, Krüger B, Im MY, Caretta L, Richter K, Mann M, Krone A, Reeve RM, Weigand M, Agrawal P, Lemesh I, Mawass MA, Fischer P, Kläui M, Beach GSD. Observation of room-temperature magnetic skyrmions and their current-driven dynamics in ultrathin metallic ferromagnets. NATURE MATERIALS 2016; 15:501-6. [PMID: 26928640 DOI: 10.1038/nmat4593] [Citation(s) in RCA: 388] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 01/29/2016] [Indexed: 05/12/2023]
Abstract
Magnetic skyrmions are topologically protected spin textures that exhibit fascinating physical behaviours and large potential in highly energy-efficient spintronic device applications. The main obstacles so far are that skyrmions have been observed in only a few exotic materials and at low temperatures, and fast current-driven motion of individual skyrmions has not yet been achieved. Here, we report the observation of stable magnetic skyrmions at room temperature in ultrathin transition metal ferromagnets with magnetic transmission soft X-ray microscopy. We demonstrate the ability to generate stable skyrmion lattices and drive trains of individual skyrmions by short current pulses along a magnetic racetrack at speeds exceeding 100 m s(-1) as required for applications. Our findings provide experimental evidence of recent predictions and open the door to room-temperature skyrmion spintronics in robust thin-film heterostructures.
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Affiliation(s)
- Seonghoon Woo
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Kai Litzius
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany
| | - Benjamin Krüger
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Mi-Young Im
- Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, Korea
| | - Lucas Caretta
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Kornel Richter
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Maxwell Mann
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Andrea Krone
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Robert M Reeve
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Markus Weigand
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Parnika Agrawal
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Ivan Lemesh
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Mohamad-Assaad Mawass
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
- Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Peter Fischer
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California, Santa Cruz, California 94056, USA
| | - Mathias Kläui
- Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
- Graduate School of Excellence Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany
| | - Geoffrey S D Beach
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Oxygen-enabled control of Dzyaloshinskii-Moriya Interaction in ultra-thin magnetic films. Sci Rep 2016; 6:24634. [PMID: 27103448 PMCID: PMC4840381 DOI: 10.1038/srep24634] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 04/01/2016] [Indexed: 11/08/2022] Open
Abstract
The search for chiral magnetic textures in systems lacking spatial inversion symmetry has attracted a massive amount of interest in the recent years with the real space observation of novel exotic magnetic phases such as skyrmions lattices, but also domain walls and spin spirals with a defined chirality. The electrical control of these textures offers thrilling perspectives in terms of fast and robust ultrahigh density data manipulation. A powerful ingredient commonly used to stabilize chiral magnetic states is the so-called Dzyaloshinskii-Moriya interaction (DMI) arising from spin-orbit coupling in inversion asymmetric magnets. Such a large antisymmetric exchange has been obtained at interfaces between heavy metals and transition metal ferromagnets, resulting in spin spirals and nanoskyrmion lattices. Here, using relativistic first-principles calculations, we demonstrate that the magnitude and sign of DMI can be entirely controlled by tuning the oxygen coverage of the magnetic film, therefore enabling the smart design of chiral magnetism in ultra-thin films. We anticipate that these results extend to other electronegative ions and suggest the possibility of electrical tuning of exotic magnetic phases.
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35
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Yang H, Thiaville A, Rohart S, Fert A, Chshiev M. Anatomy of Dzyaloshinskii-Moriya Interaction at Co/Pt Interfaces. PHYSICAL REVIEW LETTERS 2015; 115:267210. [PMID: 26765026 DOI: 10.1103/physrevlett.115.267210] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Indexed: 06/05/2023]
Abstract
The Dzyaloshinskii-Moriya interaction (DMI) has been recently recognized to play a crucial role in allowing fast domain wall dynamics driven by spin-orbit torques and the generation of magnetic Skyrmions. Here, we unveil the main features and microscopic mechanisms of DMI in Co/Pt bilayers via first principles calculations. We find that the large DMI of the bilayers has a dominant contribution from the spins of the interfacial Co layer. This DMI between the interfacical Co spins extends very weakly away from the interface and is associated with a spin-orbit coupling in the adjacent atomic layer of Pt. Furthermore, no direct correlation is found between DMI and proximity induced magnetism in Pt. These results clarify the underlying mechanisms of DMI at interfaces between ferromagnetic and heavy metals and should help optimizing material combinations for domain wall and Skyrmion-based devices.
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Affiliation(s)
- Hongxin Yang
- Univ. Grenoble Alpes, INAC-SPINTEC, 38000 Grenoble, France; CNRS, SPINTEC, 38000 Grenoble, France; and CEA, INAC-SPINTEC, 38000 Grenoble, France
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS UMR 8502, 91405 Orsay Cedex, France
| | - André Thiaville
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS UMR 8502, 91405 Orsay Cedex, France
| | - Stanislas Rohart
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS UMR 8502, 91405 Orsay Cedex, France
| | - Albert Fert
- Unité Mixte de Physique CNRS/Thales, 1 Avenue Fresnel, 91767 Palaiseau, France and Université Paris-Sud, 91405 Orsay, France
| | - Mairbek Chshiev
- Univ. Grenoble Alpes, INAC-SPINTEC, 38000 Grenoble, France; CNRS, SPINTEC, 38000 Grenoble, France; and CEA, INAC-SPINTEC, 38000 Grenoble, France
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36
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Benitez MJ, Hrabec A, Mihai AP, Moore TA, Burnell G, McGrouther D, Marrows CH, McVitie S. Magnetic microscopy and topological stability of homochiral Néel domain walls in a Pt/Co/AlOx trilayer. Nat Commun 2015; 6:8957. [PMID: 26642936 PMCID: PMC4686874 DOI: 10.1038/ncomms9957] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 10/20/2015] [Indexed: 11/09/2022] Open
Abstract
The microscopic magnetization variation in magnetic domain walls in thin films is a crucial property when considering the torques driving their dynamic behaviour. For films possessing out-of-plane anisotropy normally the presence of Néel walls is not favoured due to magnetostatic considerations. However, they have the right structure to respond to the torques exerted by the spin Hall effect. Their existence is an indicator of the interfacial Dzyaloshinskii-Moriya interaction (DMI). Here we present direct imaging of Néel domain walls with a fixed chirality in device-ready Pt/Co/AlOx films using Lorentz transmission electron and Kerr microscopies. It is shown that any independently nucleated pair of walls in our films form winding pairs when they meet that are difficult to annihilate with field, confirming that they all possess the same topological winding number. The latter is enforced by the DMI. The field required to annihilate these winding wall pairs is used to give a measure of the DMI strength. Such domain walls, which are robust against collisions with each other, are good candidates for dense data storage.
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Affiliation(s)
- M J Benitez
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland
| | - A Hrabec
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - A P Mihai
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - T A Moore
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - G Burnell
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - D McGrouther
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland
| | - C H Marrows
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - S McVitie
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland
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37
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Abstract
Magnetic skyrmions are topologically non-trivial spin textures that manifest themselves as quasiparticles in ferromagnetic thin films or noncentrosymmetric bulk materials. So far attention has focused on skyrmions stabilized either by the Dzyaloshinskii–Moriya interaction (DMI) or by dipolar interaction, where in the latter case the excitations are known as bubble skyrmions. Here we demonstrate the existence of a dynamically stabilized skyrmion, which exists even when dipolar interactions and DMI are absent. We establish how such dynamic skyrmions can be nucleated, sustained and manipulated in an effectively lossless medium under a nanocontact. As quasiparticles, they can be transported between two nanocontacts in a nanowire, even in complete absence of DMI. Conversely, in the presence of DMI, we observe that the dynamical skyrmion experiences strong breathing. All of this points towards a wide range of skyrmion manipulation, which can be studied in a much wider class of materials than considered so far. Magnetic skyrmions are particle-like spin textures with non-trivial topology which are stabilized by local magnetic interactions. Here, the authors demonstrate theoretically a class of skyrmions which are stabilized dynamically in the absence of interactions in a nanocontact spin-torque oscillator.
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38
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Thickness dependence of the interfacial Dzyaloshinskii-Moriya interaction in inversion symmetry broken systems. Nat Commun 2015; 6:7635. [PMID: 26154986 PMCID: PMC4510697 DOI: 10.1038/ncomms8635] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 05/26/2015] [Indexed: 11/08/2022] Open
Abstract
In magnetic multilayer systems, a large spin-orbit coupling at the interface between heavy metals and ferromagnets can lead to intriguing phenomena such as the perpendicular magnetic anisotropy, the spin Hall effect, the Rashba effect, and especially the interfacial Dzyaloshinskii-Moriya (IDM) interaction. This interfacial nature of the IDM interaction has been recently revisited because of its scientific and technological potential. Here we demonstrate an experimental technique to straightforwardly observe the IDM interaction, namely Brillouin light scattering. The non-reciprocal spin wave dispersions, systematically measured by Brillouin light scattering, allow not only the determination of the IDM energy densities beyond the regime of perpendicular magnetization but also the revelation of the inverse proportionality with the thickness of the magnetic layer, which is a clear signature of the interfacial nature. Altogether, our experimental and theoretical approaches involving double time Green's function methods open up possibilities for exploring magnetic hybrid structures for engineering the IDM interaction.
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39
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Universal chiral-triggered magnetization switching in confined nanodots. Sci Rep 2015; 5:10156. [PMID: 26062075 PMCID: PMC4650651 DOI: 10.1038/srep10156] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/31/2015] [Indexed: 11/08/2022] Open
Abstract
Spin orbit interactions are rapidly emerging as the key for enabling efficient current-controlled spintronic devices. Much work has focused on the role of spin-orbit coupling at heavy metal/ferromagnet interfaces in generating current-induced spin-orbit torques. However, the strong influence of the spin-orbit-derived Dzyaloshinskii-Moriya interaction (DMI) on spin textures in these materials is now becoming apparent. Recent reports suggest DMI-stabilized homochiral domain walls (DWs) can be driven with high efficiency by spin torque from the spin Hall effect. However, the influence of the DMI on the current-induced magnetization switching has not been explored nor is yet well-understood, due in part to the difficulty of disentangling spin torques and spin textures in nano-sized confined samples. Here we study the magnetization reversal of perpendicular magnetized ultrathin dots, and show that the switching mechanism is strongly influenced by the DMI, which promotes a universal chiral non-uniform reversal, even for small samples at the nanoscale. We show that ultrafast current-induced and field-induced magnetization switching consists on local magnetization reversal with domain wall nucleation followed by its propagation along the sample. These findings, not seen in conventional materials, provide essential insights for understanding and exploiting chiral magnetism for emerging spintronics applications.
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40
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Tetienne JP, Hingant T, Martínez L, Rohart S, Thiaville A, Diez LH, Garcia K, Adam JP, Kim JV, Roch JF, Miron I, Gaudin G, Vila L, Ocker B, Ravelosona D, Jacques V. The nature of domain walls in ultrathin ferromagnets revealed by scanning nanomagnetometry. Nat Commun 2015; 6:6733. [DOI: 10.1038/ncomms7733] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 02/23/2015] [Indexed: 11/09/2022] Open
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