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Si J, Yang S, Cen Y, Chen J, Huang Y, Yao Z, Kim DJ, Cai K, Yoo J, Fong X, Yang H. Energy-efficient superparamagnetic Ising machine and its application to traveling salesman problems. Nat Commun 2024; 15:3457. [PMID: 38658582 PMCID: PMC11043373 DOI: 10.1038/s41467-024-47818-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 04/11/2024] [Indexed: 04/26/2024] Open
Abstract
The growth of artificial intelligence leads to a computational burden in solving non-deterministic polynomial-time (NP)-hard problems. The Ising computer, which aims to solve NP-hard problems faces challenges such as high power consumption and limited scalability. Here, we experimentally present an Ising annealing computer based on 80 superparamagnetic tunnel junctions (SMTJs) with all-to-all connections, which solves a 70-city traveling salesman problem (TSP, 4761-node Ising problem). By taking advantage of the intrinsic randomness of SMTJs, implementing global annealing scheme, and using efficient algorithm, our SMTJ-based Ising annealer outperforms other Ising schemes in terms of power consumption and energy efficiency. Additionally, our approach provides a promising way to solve complex problems with limited hardware resources. Moreover, we propose a cross-bar array architecture for scalable integration using conventional magnetic random-access memories. Our results demonstrate that the SMTJ-based Ising computer with high energy efficiency, speed, and scalability is a strong candidate for future unconventional computing schemes.
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Affiliation(s)
- Jia Si
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
- Key Laboratory for the Physics and Chemistry of Nanodevices and Center for Carbon-based Electronics, School of Electronics, Peking University, Beijing, China
| | - Shuhan Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Yunuo Cen
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Jiaer Chen
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Yingna Huang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Zhaoyang Yao
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Dong-Jun Kim
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Kaiming Cai
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Jerald Yoo
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Xuanyao Fong
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
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2
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Taniguchi T, Imai Y. Spintronic virtual neural network by a voltage controlled ferromagnet for associative memory. Sci Rep 2024; 14:8188. [PMID: 38589599 PMCID: PMC11002033 DOI: 10.1038/s41598-024-58556-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 04/01/2024] [Indexed: 04/10/2024] Open
Abstract
Recently, an associative memory operation by a virtual oscillator network, consisting of a single spintronic oscillator, was examined to solve issues in conventional, real oscillators-based neural networks such as inhomogeneities between the oscillators. However, the spintronic oscillator still carries issues dissipating large amount of energy because it is driven by electric current. Here, we propose to use a single ferromagnet manipulated by voltage-controlled magnetic anisotropy (VCMA) effect as a fundamental element in a virtual neural network, which will contribute to significantly reducing the Joule heating caused by electric current. Instead of the oscillation in oscillator networks, magnetization relaxation dynamics were used for the associative memory operation. The associative memory operation for alphabet patterns is successfully demonstrated by giving correspondences between the colors in a pattern recognition task and the sign of a perpendicular magnetic anisotropy coefficient, which could be either positive or negative via the VCMA effect.
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Affiliation(s)
- Tomohiro Taniguchi
- National Institute of Advanced Industrial Science and Technology (AIST), Research Center for Emerging Computing Technologies, Tsukuba, Ibaraki, 305-8568, Japan.
| | - Yusuke Imai
- Graduate School of Information Science and Technology, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8656, Japan
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3
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Jiang S, Chung S, Ahlberg M, Frisk A, Khymyn R, Le QT, Mazraati H, Houshang A, Heinonen O, Åkerman J. Magnetic droplet soliton pairs. Nat Commun 2024; 15:2118. [PMID: 38459046 PMCID: PMC10923811 DOI: 10.1038/s41467-024-46404-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 02/22/2024] [Indexed: 03/10/2024] Open
Abstract
We demonstrate magnetic droplet soliton pairs in all-perpendicular spin-torque nano-oscillators (STNOs), where one droplet resides in the STNO free layer (FL) and the other in the reference layer (RL). Typically, theoretical, numerical, and experimental droplet studies have focused on the FL, with any additional dynamics in the RL entirely ignored. Here we show that there is not only significant magnetodynamics in the RL, but the RL itself can host a droplet driven by, and coexisting with, the FL droplet. Both single droplets and pairs are observed experimentally as stepwise changes and sharp peaks in the dc and differential resistance, respectively. While the single FL droplet is highly stable, the coexistence state exhibits high-power broadband microwave noise. Furthermore, micromagnetic simulations reveal that the pair dynamics display periodic, quasi-periodic, and chaotic signatures controlled by applied field and current. The strongly interacting and closely spaced droplet pair offers a unique platform for fundamental studies of highly non-linear soliton pair dynamics.
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Affiliation(s)
- S Jiang
- School of Microelectronics, South China University of Technology, 511442, Guangzhou, China
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - S Chung
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden.
- Department of Physics Education, Korea National University of Education, Cheongju, 28173, Korea.
| | - M Ahlberg
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden.
| | - A Frisk
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - R Khymyn
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - Q Tuan Le
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden
| | - H Mazraati
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden
| | - A Houshang
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - O Heinonen
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
- Seagate Technology, 7801 Computer Ave., Bloomington, MN, 55435, USA
| | - J Åkerman
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden.
- Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden.
- Center for Science and Innovation in Spintronics, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.
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4
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Nikolaev KO, Lake SR, Schmidt G, Demokritov SO, Demidov VE. Resonant generation of propagating second-harmonic spin waves in nano-waveguides. Nat Commun 2024; 15:1827. [PMID: 38418458 PMCID: PMC10902293 DOI: 10.1038/s41467-024-46108-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 02/14/2024] [Indexed: 03/01/2024] Open
Abstract
Generation of second-harmonic waves is one of the universal nonlinear phenomena that have found numerous technical applications in many modern technologies, in particular, in photonics. This phenomenon also has great potential in the field of magnonics, which considers the use of spin waves in magnetic nanostructures to implement wave-based signal processing and computing. However, due to the strong frequency dependence of the phase velocity of spin waves, resonant phase-matched generation of second-harmonic spin waves has not yet been achieved in practice. Here, we show experimentally that such a process can be realized using a combination of different modes of nano-sized spin-wave waveguides based on low-damping magnetic insulators. We demonstrate that our approach enables efficient spatially-extended energy transfer between interacting waves, which can be controlled by the intensity of the initial wave and the static magnetic field.
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Affiliation(s)
- K O Nikolaev
- Institute of Applied Physics, University of Muenster, 48149, Muenster, Germany
| | - S R Lake
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06120, Halle, Germany
| | - G Schmidt
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06120, Halle, Germany
- Interdisziplinäres Zentrum für Materialwissenschaften, Martin-Luther-Universität Halle-Wittenberg, 06120, Halle, Germany
| | - S O Demokritov
- Institute of Applied Physics, University of Muenster, 48149, Muenster, Germany.
| | - V E Demidov
- Institute of Applied Physics, University of Muenster, 48149, Muenster, Germany
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5
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Merbouche H, Divinskiy B, Gouéré D, Lebrun R, El Kanj A, Cros V, Bortolotti P, Anane A, Demokritov SO, Demidov VE. True amplification of spin waves in magnonic nano-waveguides. Nat Commun 2024; 15:1560. [PMID: 38378662 PMCID: PMC10879122 DOI: 10.1038/s41467-024-45783-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 02/05/2024] [Indexed: 02/22/2024] Open
Abstract
Magnonic nano-devices exploit magnons - quanta of spin waves - to transmit and process information within a single integrated platform that has the potential to outperform traditional semiconductor-based electronics. The main missing cornerstone of this information nanotechnology is an efficient scheme for the amplification of propagating spin waves. The recent discovery of spin-orbit torque provided an elegant mechanism for propagation losses compensation. While partial compensation of the spin-wave losses has been achieved, true amplification - the exponential increase in the spin-wave intensity during propagation - has so far remained elusive. Here we evidence the operating conditions to achieve unambiguous amplification using clocked nanoseconds-long spin-orbit torque pulses in magnonic nano-waveguides, where the effective magnetization has been engineered to be close to zero to suppress the detrimental magnon scattering. We achieve an exponential increase in the intensity of propagating spin waves up to 500% at a propagation distance of several micrometers.
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Affiliation(s)
- H Merbouche
- Institute of Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - B Divinskiy
- Institute of Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - D Gouéré
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - R Lebrun
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - A El Kanj
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - V Cros
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - P Bortolotti
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - A Anane
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - S O Demokritov
- Institute of Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany
| | - V E Demidov
- Institute of Applied Physics, University of Muenster, Corrensstrasse 2-4, 48149, Muenster, Germany.
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6
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Kajale SN, Nguyen T, Chao CA, Bono DC, Boonkird A, Li M, Sarkar D. Current-induced switching of a van der Waals ferromagnet at room temperature. Nat Commun 2024; 15:1485. [PMID: 38374025 PMCID: PMC10876566 DOI: 10.1038/s41467-024-45586-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 01/30/2024] [Indexed: 02/21/2024] Open
Abstract
Recent discovery of emergent magnetism in van der Waals magnetic materials (vdWMM) has broadened the material space for developing spintronic devices for energy-efficient computation. While there has been appreciable progress in vdWMM discovery, a solution for non-volatile, deterministic switching of vdWMMs at room temperature has been missing, limiting the prospects of their adoption into commercial spintronic devices. Here, we report the first demonstration of current-controlled non-volatile, deterministic magnetization switching in a vdW magnetic material at room temperature. We have achieved spin-orbit torque (SOT) switching of the PMA vdW ferromagnet Fe3GaTe2 using a Pt spin-Hall layer up to 320 K, with a threshold switching current density as low as [Formula: see text]1.69 [Formula: see text] 106 A cm-2 at room temperature. We have also quantitatively estimated the anti-damping-like SOT efficiency of our Fe3GaTe2/Pt bilayer system to be [Formula: see text], using the second harmonic Hall voltage measurement technique. These results mark a crucial step in making vdW magnetic materials a viable choice for the development of scalable, energy-efficient spintronic devices.
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Affiliation(s)
- Shivam N Kajale
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Thanh Nguyen
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Corson A Chao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - David C Bono
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Artittaya Boonkird
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mingda Li
- Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Deblina Sarkar
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, USA.
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7
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Dai Y, Xiong J, Ge Y, Cheng B, Wang L, Wang P, Liu Z, Yan S, Zhang C, Xu X, Shi Y, Cheong SW, Xiao C, Yang SA, Liang SJ, Miao F. Interfacial magnetic spin Hall effect in van der Waals Fe 3GeTe 2/MoTe 2 heterostructure. Nat Commun 2024; 15:1129. [PMID: 38321042 PMCID: PMC10847462 DOI: 10.1038/s41467-024-45318-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 01/19/2024] [Indexed: 02/08/2024] Open
Abstract
The spin Hall effect (SHE) allows efficient generation of spin polarization or spin current through charge current and plays a crucial role in the development of spintronics. While SHE typically occurs in non-magnetic materials and is time-reversal even, exploring time-reversal-odd (T-odd) SHE, which couples SHE to magnetization in ferromagnetic materials, offers a new charge-spin conversion mechanism with new functionalities. Here, we report the observation of giant T-odd SHE in Fe3GeTe2/MoTe2 van der Waals heterostructure, representing a previously unidentified interfacial magnetic spin Hall effect (interfacial-MSHE). Through rigorous symmetry analysis and theoretical calculations, we attribute the interfacial-MSHE to a symmetry-breaking induced spin current dipole at the vdW interface. Furthermore, we show that this linear effect can be used for implementing multiply-accumulate operations and binary convolutional neural networks with cascaded multi-terminal devices. Our findings uncover an interfacial T-odd charge-spin conversion mechanism with promising potential for energy-efficient in-memory computing.
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Affiliation(s)
- Yudi Dai
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Junlin Xiong
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Yanfeng Ge
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore, Singapore
| | - Bin Cheng
- Institute of Interdisciplinary Physical Sciences, School of Science, Nanjing University of Science and Technology, Nanjing, 210094, China.
| | - Lizheng Wang
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Pengfei Wang
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Zenglin Liu
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Shengnan Yan
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Cuiwei Zhang
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Xianghan Xu
- Center for Quantum Materials Synthesis and Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Youguo Shi
- Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Sang-Wook Cheong
- Center for Quantum Materials Synthesis and Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Cong Xiao
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau, SAR, China.
- Department of Physics, University of Hong Kong, Hong Kong, China.
- HKU-UCAS Joint Institute of Theoretical and Computational Physics at Hong Kong, Hong Kong, China.
| | - Shengyuan A Yang
- Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau, SAR, China
| | - Shi-Jun Liang
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
| | - Feng Miao
- National Laboratory of Solid State Microstructures, Institute of Brain-Inspired Intelligence, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
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8
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Taniguchi T. Bifurcation to complex dynamics in largely modulated voltage-controlled parametric oscillator. Sci Rep 2024; 14:2891. [PMID: 38316855 PMCID: PMC10844235 DOI: 10.1038/s41598-024-53503-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 02/01/2024] [Indexed: 02/07/2024] Open
Abstract
An experimental demonstration of a parametric oscillation of a magnetization in a ferromagnet was performed recently by applying a microwave voltage, indicating the potential to be applied in a switching method in non-volatile memories. In the previous works, the modulation of a perpendicular magnetic anisotropy field produced by the microwave voltage was small compared with an external magnetic field pointing in an in-plane direction. A recent trend is, however, opposite, where an efficiency of the voltage controlled magnetic anisotropy (VCMA) effect is increased significantly by material research and thus, the modulated magnetic anisotropy field can be larger than the external magnetic field. Here, we solved the Landau-Lifshitz-Gilbert equation numerically and investigated the magnetization dynamics driven under a wide range of the microwave VCMA effect. We evaluated bifurcation diagrams, which summarize local maxima of the magnetization dynamics. For low modulation amplitudes, the local maximum is a single point because the dynamics is the periodic parametric oscillation. The bifurcation diagrams show distributions of the local maxima when the microwave magnetic anisotropy field becomes larger than the external magnetic field. The appearance of this broadened distribution indicates complex dynamics such as chaotic and transient-chaotic behaviors, which were confirmed from an analysis of temporal dynamics.
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Affiliation(s)
- Tomohiro Taniguchi
- National Institute of Advanced Industrial Science and Technology (AIST), Research Center for Emerging Computing Technologies, Tsukuba, Ibaraki, 305-8568, Japan.
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9
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Wittrock S, Perna S, Lebrun R, Ho K, Dutra R, Ferreira R, Bortolotti P, Serpico C, Cros V. Non-hermiticity in spintronics: oscillation death in coupled spintronic nano-oscillators through emerging exceptional points. Nat Commun 2024; 15:971. [PMID: 38302454 PMCID: PMC10834588 DOI: 10.1038/s41467-023-44436-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 12/13/2023] [Indexed: 02/03/2024] Open
Abstract
The emergence of exceptional points (EPs) in the parameter space of a non-hermitian (2D) eigenvalue problem has long been interest in mathematical physics, however, only in the last decade entered the scope of experiments. In coupled systems, EPs give rise to unique physical phenomena, and enable the development of highly sensitive sensors. Here, we demonstrate at room temperature the emergence of EPs in coupled spintronic nanoscale oscillators and exploit the system's non-hermiticity. We observe amplitude death of self-oscillations and other complex dynamics, and develop a linearized non-hermitian model of the coupled spintronic system, which describes the main experimental features. The room temperature operation, and CMOS compatibility of our spintronic nanoscale oscillators means that they are ready to be employed in a variety of applications, such as field, current or rotation sensors, radiofrequeny and wireless devices, and in dedicated neuromorphic computing hardware. Furthermore, their unique and versatile properties, notably their large nonlinear behavior, open up unprecedented perspectives in experiments as well as in theory on the physics of exceptional points expanding to strongly nonlinear systems.
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Affiliation(s)
- Steffen Wittrock
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France.
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109, Berlin, Germany.
| | - Salvatore Perna
- Department of Electrical Engineering and ICT, University of Naples Federico II, 80125, Naples, Italy
| | - Romain Lebrun
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France
| | - Katia Ho
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France
| | - Roberta Dutra
- Centro Brasileiro de Pesquisas Fésicas (CBPF), Rua Dr. Xavier Sigaud 150, Rio de Janeiro, 22290-180, Brazil
| | - Ricardo Ferreira
- International Iberian Nanotechnology Laboratory (INL), 471531, Braga, Portugal
| | - Paolo Bortolotti
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France
| | - Claudio Serpico
- Department of Electrical Engineering and ICT, University of Naples Federico II, 80125, Naples, Italy
| | - Vincent Cros
- Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, 1 Avenue Augustin Fresnel, 91767, Palaiseau, France.
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10
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Jensen JH, Strømberg A, Breivik I, Penty A, Niño MA, Khaliq MW, Foerster M, Tufte G, Folven E. Clocked dynamics in artificial spin ice. Nat Commun 2024; 15:964. [PMID: 38302504 PMCID: PMC10834408 DOI: 10.1038/s41467-024-45319-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 01/19/2024] [Indexed: 02/03/2024] Open
Abstract
Artificial spin ice (ASI) are nanomagnetic metamaterials with a wide range of emergent properties. Through local interactions, the magnetization of the nanomagnets self-organize into extended magnetic domains. However, controlling when, where and how domains change has proven difficult, yet is crucial for technological applications. Here, we introduce astroid clocking, which offers significant control of ASI dynamics in both time and space. Astroid clocking unlocks a discrete, step-wise and gradual dynamical process within the metamaterial. Notably, our method employs global fields to selectively manipulate local features within the ASI. Sequences of these clock fields drive domain dynamics. We demonstrate, experimentally and in simulations, how astroid clocking of pinwheel ASI enables ferromagnetic domains to be gradually grown or reversed at will. Richer dynamics arise when the clock protocol allows both growth and reversal to occur simultaneously. With astroid clocking, complex spatio-temporal behaviors of magnetic metamaterials become easily controllable with high fidelity.
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Affiliation(s)
- Johannes H Jensen
- Department of Computer Science, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Anders Strømberg
- Department of Electronic Systems, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Ida Breivik
- Department of Electronic Systems, Norwegian University of Science and Technology, Trondheim, Norway
| | - Arthur Penty
- Department of Computer Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Miguel Angel Niño
- ALBA Synchrotron Light Facility, Carrer de la Llum 2 - 26, Cerdanyola del Vallés, 08290, Barcelona, Spain
| | - Muhammad Waqas Khaliq
- ALBA Synchrotron Light Facility, Carrer de la Llum 2 - 26, Cerdanyola del Vallés, 08290, Barcelona, Spain
| | - Michael Foerster
- ALBA Synchrotron Light Facility, Carrer de la Llum 2 - 26, Cerdanyola del Vallés, 08290, Barcelona, Spain
| | - Gunnar Tufte
- Department of Computer Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Erik Folven
- Department of Electronic Systems, Norwegian University of Science and Technology, Trondheim, Norway
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11
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Huang C, Sun R, Bao L, Tian X, Pan C, Li M, Shen W, Guo K, Wang B, Lu X, Gao S. A hard molecular nanomagnet from confined paramagnetic 3d-4f spins inside a fullerene cage. Nat Commun 2023; 14:8443. [PMID: 38114506 PMCID: PMC10730828 DOI: 10.1038/s41467-023-44194-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 12/04/2023] [Indexed: 12/21/2023] Open
Abstract
Reducing inter-spin distance can enhance magnetic interactions and allow for the realization of outstanding magnetic properties. However, achieving reduced distances is technically challenging. Here, we construct a 3d-4f metal cluster (Dy2VN) inside a C80 cage, affording a heretofore unseen metallofullerene containing both paramagnetic 3d and 4f metal ions. The significantly suppressed 3d-4f (Dy-V) distances, due to the unique cage confinement effect, were observed by crystallographic and theoretical analysis of Dy2VN@Ih(7)-C80. These reduced distances result in an enhanced magnetic coupling (Jtotal, Dy-V = 53.30 cm-1; Jtotal, Dy-Dy = -6.25 cm-1), leading to a high magnetic blocking temperature compared to reported 3d-4f single-molecule magnets and strong coercive field of 2.73 Tesla. Our work presents a new class of single-molecule magnets with both paramagnetic 3d and 4f metals confined in a fullerene cage, offering superior and tunable magnetic properties due to the unique cage confinement effect and the diverse composition of the entrapped magnetic core.
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Affiliation(s)
- Chenli Huang
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037, Luoyu Road, Wuhan, 430074, P. R. China
| | - Rong Sun
- Beijing National Laboratory of Molecular Science, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Lipiao Bao
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037, Luoyu Road, Wuhan, 430074, P. R. China.
| | - Xinyue Tian
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037, Luoyu Road, Wuhan, 430074, P. R. China
| | - Changwang Pan
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037, Luoyu Road, Wuhan, 430074, P. R. China
| | - Mengyang Li
- School of Physics, Xidian University, Xi'an, 710071, China
| | - Wangqiang Shen
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037, Luoyu Road, Wuhan, 430074, P. R. China
| | - Kun Guo
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037, Luoyu Road, Wuhan, 430074, P. R. China
| | - Bingwu Wang
- Beijing National Laboratory of Molecular Science, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China.
| | - Xing Lu
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037, Luoyu Road, Wuhan, 430074, P. R. China.
- College of Chemistry and Chemical Engineering, Hainan University, No. 58, Renmin Avenue, Haikou, 570228, P. R. China.
| | - Song Gao
- Beijing National Laboratory of Molecular Science, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
- Spin-X Institute, School of Chemistry and Chemical Engineering, State Key Laboratory of Luminescent Materials and Devices, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, Guangzhou, 510641, P. R. China
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12
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Lee SH, Kim M, Whang HS, Nam YS, Park JH, Kim K, Kim M, Shin J, Yu JS, Yoon J, Chang JY, Kim DH, Choe SB. Position error-free control of magnetic domain-wall devices via spin-orbit torque modulation. Nat Commun 2023; 14:7648. [PMID: 37996445 PMCID: PMC10667336 DOI: 10.1038/s41467-023-43468-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 11/10/2023] [Indexed: 11/25/2023] Open
Abstract
Magnetic domain-wall devices such as racetrack memory and domain-wall shift registers facilitate massive data storage as hard disk drives with low power portability as flash memory devices. The key issue to be addressed is how perfectly the domain-wall motion can be controlled without deformation, as it can replace the mechanical motion of hard disk drives. However, such domain-wall motion in real media is subject to the stochasticity of thermal agitation with quenched disorders, resulting in severe deformations with pinning and tilting. To sort out the problem, we propose and demonstrate a new concept of domain-wall control with a position error-free scheme. The primary idea involves spatial modulation of the spin-orbit torque along nanotrack devices, where the boundary of modulation possesses broken inversion symmetry. In this work, by showing the unidirectional motion of domain wall with position-error free manner, we provide an important missing piece in magnetic domain-wall device development.
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Affiliation(s)
- Seong-Hyub Lee
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Myeonghoe Kim
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Hyun-Seok Whang
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yune-Seok Nam
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jung-Hyun Park
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Kitae Kim
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Minhwan Kim
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
- Center for Spintronics, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Jiho Shin
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Ji-Sung Yu
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jaesung Yoon
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jun-Young Chang
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
- Center for Spintronics, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Duck-Ho Kim
- Center for Spintronics, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Sug-Bong Choe
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea.
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13
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Frost W, Carpenter R, Couet S, O'Grady K, Vallejo Fernandez G. Distributions of easy axes and reversal processes in patterned MRAM arrays. Sci Rep 2023; 13:20490. [PMID: 37993658 PMCID: PMC10665439 DOI: 10.1038/s41598-023-47629-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/16/2023] [Indexed: 11/24/2023] Open
Abstract
The distribution of the easy-axes in an array of MRAM cells is a vital parameter to understand the switching and characteristics of the devices. By measuring the coercivity as a function of applied-field angle, and remaining close to the perpendicular orientation, a classic Stoner-Wohlfarth approximation has been applied to the resulting variation to determine the standard deviation, [Formula: see text], of a Gaussian distribution of the orientation of the easy-magnetisation directions. In this work we have compared MRAM arrays with nominal cells sizes of 20 nm and 60 nm and a range of free layer thicknesses. We have found that a smaller diameter cell will have a wider switching-field distribution with a standard deviation [Formula: see text]. The MRAM arrays consist of pillars produced by etching a multilayer thin film. This value of [Formula: see text] is dominated by pillar uniformity and edge effects controlling the reversal, reinforcing the need for ever-improving etch processes. This is compared to larger pillars, with distributions as low as [Formula: see text]. Furthermore we found that the distribution broadens from [Formula: see text] to [Formula: see text] with free layer thickness in larger pillars and that thinner films had a more uniform easy-axis orientation. For the 20 nm pillars the non-uniform size distribution of the pillars, with a large and unknown error in the free-layer volume, was highlighted as it was found that the activation volume for the reversal of the free layer 930 nm[Formula: see text] was larger than the nominal physical volume of the free layer. However for the 60 nm pillars, the activation volume was measured to be equal to one fifth of their physical volume. This implies that the smaller pillars effectively reverse as one entity while the larger pillars reverse via an incoherent mechanism of nucleation and propagation.
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Affiliation(s)
- William Frost
- School of Physics, Engineering and Technology, University of York, Heslington, YO10 5DD, UK.
| | | | | | - Kevin O'Grady
- School of Physics, Engineering and Technology, University of York, Heslington, YO10 5DD, UK
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14
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Hajiaghajani A, Rwei P, Afandizadeh Zargari AH, Escobar AR, Kurdahi F, Khine M, Tseng P. Amphibious epidermal area networks for uninterrupted wireless data and power transfer. Nat Commun 2023; 14:7522. [PMID: 37980425 PMCID: PMC10657464 DOI: 10.1038/s41467-023-43344-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 11/08/2023] [Indexed: 11/20/2023] Open
Abstract
The human body exhibits complex, spatially distributed chemo-electro-mechanical processes that must be properly captured for emerging applications in virtual/augmented reality, precision health, activity monitoring, bionics, and more. A key factor in enabling such applications involves the seamless integration of multipurpose wearable sensors across the human body in different environments, spanning from indoor settings to outdoor landscapes. Here, we report a versatile epidermal body area network ecosystem that enables wireless power and data transmission to and from battery-free wearable sensors with continuous functionality from dry to underwater settings. This is achieved through an artificial near field propagation across the chain of biocompatible, magneto-inductive metamaterials in the form of stretchable waterborne skin patches-these are fully compatible with pre-existing consumer electronics. Our approach offers uninterrupted, self-powered communication for human status monitoring in harsh environments where traditional wireless solutions (such as Bluetooth, Wi-Fi or cellular) are unable to communicate reliably.
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Affiliation(s)
- Amirhossein Hajiaghajani
- Department of Electrical Engineering and Computer Science, University of California, Irvine, CA, USA
| | - Patrick Rwei
- Department of Biomedical Engineering, University of California, Irvine, CA, USA
| | - Amir Hosein Afandizadeh Zargari
- Department of Electrical Engineering and Computer Science, University of California, Irvine, CA, USA
- Center for Embedded and Cyber-physical Systems, University of California, Irvine, CA, USA
| | | | - Fadi Kurdahi
- Department of Electrical Engineering and Computer Science, University of California, Irvine, CA, USA
- Center for Embedded and Cyber-physical Systems, University of California, Irvine, CA, USA
| | - Michelle Khine
- Department of Biomedical Engineering, University of California, Irvine, CA, USA
| | - Peter Tseng
- Department of Electrical Engineering and Computer Science, University of California, Irvine, CA, USA.
- Department of Biomedical Engineering, University of California, Irvine, CA, USA.
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15
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Yun C, Liang Z, Hrabec A, Liu Z, Huang M, Wang L, Xiao Y, Fang Y, Li W, Yang W, Hou Y, Yang J, Heyderman LJ, Gambardella P, Luo Z. Electrically programmable magnetic coupling in an Ising network exploiting solid-state ionic gating. Nat Commun 2023; 14:6367. [PMID: 37821464 PMCID: PMC10567909 DOI: 10.1038/s41467-023-41830-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 09/20/2023] [Indexed: 10/13/2023] Open
Abstract
Two-dimensional arrays of magnetically coupled nanomagnets provide a mesoscopic platform for exploring collective phenomena as well as realizing a broad range of spintronic devices. In particular, the magnetic coupling plays a critical role in determining the nature of the cooperative behavior and providing new functionalities in nanomagnet-based devices. Here, we create coupled Ising-like nanomagnets in which the coupling between adjacent nanomagnetic regions can be reversibly converted between parallel and antiparallel through solid-state ionic gating. This is achieved with the voltage-control of the magnetic anisotropy in a nanosized region where the symmetric exchange interaction favors parallel alignment and the antisymmetric exchange interaction, namely the Dzyaloshinskii-Moriya interaction, favors antiparallel alignment of the nanomagnet magnetizations. Applying this concept to a two-dimensional lattice, we demonstrate a voltage-controlled phase transition in artificial spin ices. Furthermore, we achieve an addressable control of the individual couplings and realize an electrically programmable Ising network, which opens up new avenues to design nanomagnet-based logic devices and neuromorphic computers.
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Affiliation(s)
- Chao Yun
- State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
- School of Materials Science and Engineering, Peking University, 100871, Beijing, China
| | - Zhongyu Liang
- State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Aleš Hrabec
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093, Zurich, Switzerland
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, 5232, Villigen PSI, Switzerland
- Laboratory for Magnetism and Interface Physics, Department of Materials, ETH Zurich, 8093, Zurich, Switzerland
| | - Zhentao Liu
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093, Zurich, Switzerland
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, 5232, Villigen PSI, Switzerland
| | - Mantao Huang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Leran Wang
- State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Yifei Xiao
- Division of Functional Materials, Central Iron and Steel Research Institute Group, 100081, Beijing, China
| | - Yikun Fang
- Division of Functional Materials, Central Iron and Steel Research Institute Group, 100081, Beijing, China
| | - Wei Li
- Division of Functional Materials, Central Iron and Steel Research Institute Group, 100081, Beijing, China
| | - Wenyun Yang
- State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - Yanglong Hou
- School of Materials Science and Engineering, Peking University, 100871, Beijing, China
| | - Jinbo Yang
- State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China
| | - 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.
| | - Zhaochu Luo
- State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 100871, Beijing, China.
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16
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Mayes D, Farahmand F, Grossnickle M, Lohmann M, Aldosary M, Li J, Aji V, Shi J, Song JCW, Gabor NM. Mapping the intrinsic photocurrent streamlines through micromagnetic heterostructure devices. Proc Natl Acad Sci U S A 2023; 120:e2221815120. [PMID: 37722037 PMCID: PMC10523491 DOI: 10.1073/pnas.2221815120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 08/08/2023] [Indexed: 09/20/2023] Open
Abstract
Photocurrent in quantum materials is often collected at global contacts far away from the initial photoexcitation. This collection process is highly nonlocal. It involves an intricate spatial pattern of photocurrent flow (streamlines) away from its primary photoexcitation that depends sensitively on the configuration of current collecting contacts as well as the spatial nonuniformity and tensor structure of conductivity. Direct imaging to track photocurrent streamlines is challenging. Here, we demonstrate a microscopy method to image photocurrent streamlines through ultrathin heterostructure devices comprising platinum on yttrium iron garnet (YIG). We accomplish this by combining scanning photovoltage microscopy with a uniform rotating magnetic field. Here, local photocurrent is generated through a photo-Nernst type effect with its direction controlled by the external magnetic field. This enables the mapping of photocurrent streamlines in a variety of geometries that include conventional Hall bar-type devices, but also unconventional wing-shaped devices called electrofoils. In these, we find that photocurrent streamlines display contortion, compression, and expansion behavior depending on the shape and angle of attack of the electrofoil devices, much in the same way as tracers in a wind tunnel map the flow of air around an aerodynamic airfoil. This affords a powerful tool to visualize and characterize charge flow in optoelectronic devices.
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Affiliation(s)
- David Mayes
- Department of Physics and Astronomy, University of California, Riverside, CA92521
- Laboratory of Quantum Materials Optoelectronics, University of California, Riverside, CA92521
| | - Farima Farahmand
- Department of Physics and Astronomy, University of California, Riverside, CA92521
- Laboratory of Quantum Materials Optoelectronics, University of California, Riverside, CA92521
| | - Maxwell Grossnickle
- Department of Physics and Astronomy, University of California, Riverside, CA92521
- Laboratory of Quantum Materials Optoelectronics, University of California, Riverside, CA92521
| | - Mark Lohmann
- Department of Physics and Astronomy, University of California, Riverside, CA92521
| | - Mohammed Aldosary
- Department of Physics and Astronomy, University of California, Riverside, CA92521
| | - Junxue Li
- Department of Physics and Astronomy, University of California, Riverside, CA92521
| | - Vivek Aji
- Department of Physics and Astronomy, University of California, Riverside, CA92521
| | - Jing Shi
- Department of Physics and Astronomy, University of California, Riverside, CA92521
| | - Justin C. W. Song
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore637371, Singapore
| | - Nathaniel M. Gabor
- Department of Physics and Astronomy, University of California, Riverside, CA92521
- Laboratory of Quantum Materials Optoelectronics, University of California, Riverside, CA92521
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17
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Chen K, Duong BTV, Ahmed SU, Dhavarasa P, Wang Z, Labib M, Flynn C, Xu J, Zhang YY, Wang H, Yang X, Das J, Zargartalebi H, Ma Y, Kelley SO. A magneto-activated nanoscale cytometry platform for molecular profiling of small extracellular vesicles. Nat Commun 2023; 14:5576. [PMID: 37696888 PMCID: PMC10495366 DOI: 10.1038/s41467-023-41285-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 08/30/2023] [Indexed: 09/13/2023] Open
Abstract
Exosomal PD-L1 (exoPD-L1) has recently received significant attention as a biomarker predicting immunotherapeutic responses involving the PD1/PD-L1 pathway. However, current technologies for exosomal analysis rely primarily on bulk measurements that do not consider the heterogeneity found within exosomal subpopulations. Here, we present a nanoscale cytometry platform NanoEPIC, enabling phenotypic sorting and exoPD-L1 profiling from blood plasma. We highlight the efficacy of NanoEPIC in monitoring anti-PD-1 immunotherapy through the interrogation of exoPD-L1. NanoEPIC generates signature exoPD-L1 patterns in responders and non-responders. In mice treated with PD1-targeted immunotherapy, exoPD-L1 is correlated with tumor growth, PD-L1 burden in tumors, and the immune suppression of CD8+ tumor-infiltrating lymphocytes. Small extracellular vesicles (sEVs) with different PD-L1 expression levels display distinctive inhibitory effects on CD8 + T cells. NanoEPIC offers robust, high-throughput profiling of exosomal markers, enabling sEV subpopulation analysis. This platform holds the potential for enhanced cancer screening, personalized treatment, and therapeutic response monitoring.
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Affiliation(s)
- Kangfu Chen
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, Canada
| | - Bill T V Duong
- Department of Chemistry, University of Toronto, Toronto, ON, Canada
| | - Sharif U Ahmed
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, Canada
| | | | - Zongjie Wang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Mahmoud Labib
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, Canada
- Department of Chemistry, Northwestern University, Evanston, IL, USA
- Peninsula Medical School, Faculty of Health, University of Plymouth, Plymouth, UK
| | - Connor Flynn
- Department of Chemistry, University of Toronto, Toronto, ON, Canada
- Department of Chemistry, Northwestern University, Evanston, IL, USA
| | - Jingya Xu
- Department of Chemistry, University of Toronto, Toronto, ON, Canada
| | - Yi Y Zhang
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, Canada
| | - Hansen Wang
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, Canada
| | - Xiaolong Yang
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, Canada
| | - Jagotamoy Das
- Department of Chemistry, Northwestern University, Evanston, IL, USA
| | - Hossein Zargartalebi
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, Canada
| | - Yuan Ma
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, Canada
| | - Shana O Kelley
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, Canada.
- Department of Chemistry, University of Toronto, Toronto, ON, Canada.
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.
- Department of Chemistry, Northwestern University, Evanston, IL, USA.
- Institute for Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
- Chan Zuckerberg Biohub Chicago, Chicago, IL, USA.
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18
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Huang M, Sun Z, Yan G, Xie H, Agarwal N, Ye G, Sung SH, Lu H, Zhou J, Yan S, Tian S, Lei H, Hovden R, He R, Wang H, Zhao L, Du CR. Revealing intrinsic domains and fluctuations of moiré magnetism by a wide-field quantum microscope. Nat Commun 2023; 14:5259. [PMID: 37644000 PMCID: PMC10465594 DOI: 10.1038/s41467-023-40543-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 08/01/2023] [Indexed: 08/31/2023] Open
Abstract
Moiré magnetism featured by stacking engineered atomic registry and lattice interactions has recently emerged as an appealing quantum state of matter at the forefront of condensed matter physics research. Nanoscale imaging of moiré magnets is highly desirable and serves as a prerequisite to investigate a broad range of intriguing physics underlying the interplay between topology, electronic correlations, and unconventional nanomagnetism. Here we report spin defect-based wide-field imaging of magnetic domains and spin fluctuations in twisted double trilayer (tDT) chromium triiodide CrI3. We explicitly show that intrinsic moiré domains of opposite magnetizations appear over arrays of moiré supercells in low-twist-angle tDT CrI3. In contrast, spin fluctuations measured in tDT CrI3 manifest little spatial variations on the same mesoscopic length scale due to the dominant driving force of intralayer exchange interaction. Our results enrich the current understanding of exotic magnetic phases sustained by moiré magnetism and highlight the opportunities provided by quantum spin sensors in probing microscopic spin related phenomena on two-dimensional flatland.
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Affiliation(s)
- Mengqi Huang
- Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Zeliang Sun
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Gerald Yan
- Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Hongchao Xie
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Nishkarsh Agarwal
- Department of Material Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Gaihua Ye
- Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Suk Hyun Sung
- Department of Material Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Hanyi Lu
- Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Jingcheng Zhou
- Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Shaohua Yan
- Laboratory for Neutron Scattering, and Beijing Key Laboratory of Optoelectronic Functional Materials MicroNano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China
| | - Shangjie Tian
- Laboratory for Neutron Scattering, and Beijing Key Laboratory of Optoelectronic Functional Materials MicroNano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China
- School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Hechang Lei
- Laboratory for Neutron Scattering, and Beijing Key Laboratory of Optoelectronic Functional Materials MicroNano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China
| | - Robert Hovden
- Department of Material Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Rui He
- Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, TX, 79409, USA
| | - Hailong Wang
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Center for Memory and Recording Research, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Liuyan Zhao
- Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Chunhui Rita Du
- Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA.
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
- Center for Memory and Recording Research, University of California, San Diego, La Jolla, CA, 92093, USA.
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19
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Lin AA, Shen H, Spychalski G, Carpenter EL, Issadore D. Modeling and optimization of parallelized immunomagnetic nanopore sorting for surface marker specific isolation of extracellular vesicles from complex media. Sci Rep 2023; 13:13292. [PMID: 37587235 PMCID: PMC10432479 DOI: 10.1038/s41598-023-39746-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/30/2023] [Indexed: 08/18/2023] Open
Abstract
The isolation of specific subpopulations of extracellular vesicles (EVs) based on their expression of surface markers poses a significant challenge due to their nanoscale size (< 800 nm), their heterogeneous surface marker expression, and the vast number of background EVs present in clinical specimens (1010-1012 EVs/mL in blood). Highly parallelized nanomagnetic sorting using track etched magnetic nanopore (TENPO) chips has achieved precise immunospecific sorting with high throughput and resilience to clogging. However, there has not yet been a systematic study of the design parameters that control the trade-offs in throughput, target EV recovery, and ability to discard background EVs in this approach. We combine finite-element simulation and experimental characterization of TENPO chips to elucidate design rules to isolate EV subpopulations from blood. We demonstrate the utility of this approach by reducing device background > 10× relative to prior published designs without sacrificing recovery of the target EVs by selecting pore diameter, number of membranes placed in series, and flow rate. We compare TENPO-isolated EVs to those of gold-standard methods of EV isolation and demonstrate its utility for wide application and modularity by targeting subpopulations of EVs from multiple models of disease including lung cancer, pancreatic cancer, and liver cancer.
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Affiliation(s)
- Andrew A Lin
- Department of Bioengineering, University of Pennsylvania, 210 S. 33rd St., Philadelphia, PA, 19104, USA
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd., Philadelphia, PA, 19104, USA
| | - Hanfei Shen
- Department of Bioengineering, University of Pennsylvania, 210 S. 33rd St., Philadelphia, PA, 19104, USA
| | - Griffin Spychalski
- Department of Bioengineering, University of Pennsylvania, 210 S. 33rd St., Philadelphia, PA, 19104, USA
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd., Philadelphia, PA, 19104, USA
| | - Erica L Carpenter
- Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd., Philadelphia, PA, 19104, USA
| | - David Issadore
- Department of Bioengineering, University of Pennsylvania, 210 S. 33rd St., Philadelphia, PA, 19104, USA.
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20
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Ren H, Zheng XY, Channa S, Wu G, O'Mahoney DA, Suzuki Y, Kent AD. Hybrid spin Hall nano-oscillators based on ferromagnetic metal/ferrimagnetic insulator heterostructures. Nat Commun 2023; 14:1406. [PMID: 36918562 DOI: 10.1038/s41467-023-37028-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 03/01/2023] [Indexed: 03/16/2023] Open
Abstract
Spin-Hall nano-oscillators (SHNOs) are promising spintronic devices to realize current controlled GHz frequency signals in nanoscale devices for neuromorphic computing and creating Ising systems. However, traditional SHNOs devices based on transition metals have high auto-oscillation threshold currents as well as low quality factors and output powers. Here we demonstrate a new type of hybrid SHNO based on a permalloy (Py) ferromagnetic-metal nanowire and low-damping ferrimagnetic insulator, in the form of epitaxial lithium aluminum ferrite (LAFO) thin films. The superior characteristics of such SHNOs are associated with the excitation of larger spin-precession angles and volumes. We further find that the presence of the ferrimagnetic insulator enhances the auto-oscillation amplitude of spin-wave edge modes, consistent with our micromagnetic modeling. This hybrid SHNO expands spintronic applications, including providing new means of coupling multiple SHNOs for neuromorphic computing and advancing magnonics.
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21
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Iurchuk V, Pablo-Navarro J, Hula T, Narkowicz R, Hlawacek G, Körber L, Kákay A, Schultheiss H, Fassbender J, Lenz K, Lindner J. Tailoring crosstalk between localized 1D spin-wave nanochannels using focused ion beams. Sci Rep 2023; 13:764. [PMID: 36641510 DOI: 10.1038/s41598-022-27249-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 12/28/2022] [Indexed: 01/15/2023] Open
Abstract
1D spin-wave conduits are envisioned as nanoscale components of magnonics-based logic and computing schemes for future generation electronics. À-la-carte methods of versatile control of the local magnetization dynamics in such nanochannels are highly desired for efficient steering of the spin waves in magnonic devices. Here, we present a study of localized dynamical modes in 1-[Formula: see text]m-wide permalloy conduits probed by microresonator ferromagnetic resonance technique. We clearly observe the lowest-energy edge mode in the microstrip after its edges were finely trimmed by means of focused Ne[Formula: see text] ion irradiation. Furthermore, after milling the microstrip along its long axis by focused ion beams, creating consecutively [Formula: see text]50 and [Formula: see text]100 nm gaps, additional resonances emerge and are attributed to modes localized at the inner edges of the separated strips. To visualize the mode distribution, spatially resolved Brillouin light scattering microscopy was used showing an excellent agreement with the ferromagnetic resonance data and confirming the mode localization at the outer/inner edges of the strips depending on the magnitude of the applied magnetic field. Micromagnetic simulations confirm that the lowest-energy modes are localized within [Formula: see text]15-nm-wide regions at the edges of the strips and their frequencies can be tuned in a wide range (up to 5 GHz) by changing the magnetostatic coupling (i.e., spatial separation) between the microstrips.
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22
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Imai Y, Nakajima K, Tsunegi S, Taniguchi T. Input-driven chaotic dynamics in vortex spin-torque oscillator. Sci Rep 2022; 12:21651. [PMID: 36522401 PMCID: PMC9755258 DOI: 10.1038/s41598-022-26018-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022] Open
Abstract
A new research topic in spintronics relating to the operation principles of brain-inspired computing is input-driven magnetization dynamics in nanomagnet. In this paper, the magnetization dynamics in a vortex spin-torque oscillator driven by a series of random magnetic field are studied through a numerical simulation of the Thiele equation. It is found that input-driven synchronization occurs in the weak perturbation limit, as found recently. As well, chaotic behavior is newly found to occur in the vortex core dynamics for a wide range of parameters, where synchronized behavior is disrupted by an intermittency. Ordered and chaotic dynamical phases are examined by evaluating the Lyapunov exponent. The relation between the dynamical phase and the computational capability of physical reservoir computing is also studied.
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Affiliation(s)
- Yusuke Imai
- grid.208504.b0000 0001 2230 7538Research Center for Emerging Computing Technologies, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 Japan
| | - Kohei Nakajima
- grid.26999.3d0000 0001 2151 536XGraduate School of Information Science and Technology, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8656 Japan
| | - Sumito Tsunegi
- grid.208504.b0000 0001 2230 7538Research Center for Emerging Computing Technologies, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 Japan ,grid.419082.60000 0004 1754 9200Japan Science and Technology Agency (JST), PRESTO, Saitama, 332-0012 Japan
| | - Tomohiro Taniguchi
- grid.208504.b0000 0001 2230 7538Research Center for Emerging Computing Technologies, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 Japan
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23
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Fiorentini S, Bendra M, Ender J, de Orio RL, Goes W, Selberherr S, Sverdlov V. Spin and charge drift-diffusion in ultra-scaled MRAM cells. Sci Rep 2022; 12:20958. [PMID: 36471161 PMCID: PMC9723118 DOI: 10.1038/s41598-022-25586-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
Designing advanced single-digit shape-anisotropy MRAM cells requires an accurate evaluation of spin currents and torques in magnetic tunnel junctions (MTJs) with elongated free and reference layers. For this purpose, we extended the analysis approach successfully used in nanoscale metallic spin valves to MTJs by introducing proper boundary conditions for the spin currents at the tunnel barrier interfaces, and by employing a conductivity locally dependent on the angle between the magnetization vectors for the charge current. The experimentally measured voltage and angle dependencies of the torques acting on the free layer are thereby accurately reproduced. The switching behavior of ultra-scaled MRAM cells is in agreement with recent experiments on shape-anisotropy MTJs. Using our extended approach is absolutely essential to accurately capture the interplay of the Slonczewski and Zhang-Li torque contributions acting on a textured magnetization in composite free layers with the inclusion of several MgO barriers.
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Affiliation(s)
- Simone Fiorentini
- Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Vienna, Austria ,grid.5329.d0000 0001 2348 4034Institute for Microelectronics, TU Wien, Gußhausstraße 27–29/E360, 1040 Vienna, Austria
| | - Mario Bendra
- Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Vienna, Austria ,grid.5329.d0000 0001 2348 4034Institute for Microelectronics, TU Wien, Gußhausstraße 27–29/E360, 1040 Vienna, Austria
| | - Johannes Ender
- Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Vienna, Austria ,grid.5329.d0000 0001 2348 4034Institute for Microelectronics, TU Wien, Gußhausstraße 27–29/E360, 1040 Vienna, Austria
| | - Roberto L. de Orio
- Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Vienna, Austria ,grid.5329.d0000 0001 2348 4034Institute for Microelectronics, TU Wien, Gußhausstraße 27–29/E360, 1040 Vienna, Austria
| | | | - Siegfried Selberherr
- grid.5329.d0000 0001 2348 4034Institute for Microelectronics, TU Wien, Gußhausstraße 27–29/E360, 1040 Vienna, Austria
| | - Viktor Sverdlov
- Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Vienna, Austria ,grid.5329.d0000 0001 2348 4034Institute for Microelectronics, TU Wien, Gußhausstraße 27–29/E360, 1040 Vienna, Austria
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24
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Rychły-Gruszecka J, Walowski J, Denker C, Tubandt T, Münzenberg M, Kłos JW. Shaping the spin wave spectra of planar 1D magnonic crystals by the geometrical constraints. Sci Rep 2022; 12:20678. [PMID: 36450794 DOI: 10.1038/s41598-022-24969-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 11/22/2022] [Indexed: 12/03/2022] Open
Abstract
We present experimental and numerical studies demonstrating the influence of geometrical parameters on the fundamental spin-wave mode in planar 1D magnonic crystals. The investigated magnonic crystals consist of flat stripes separated by air gaps. The adjustment of geometrical parameters allows tailoring of the spin-wave frequencies. The width of stripes and the width of gaps between them affect spin-wave frequencies in two ways. First, directly by geometrical constraints confining the spin waves inside the stripes. Second, indirectly by spin-wave pinning, freeing the spin waves to a different extent on the edges of stripes. Experimentally, the fundamental spin-wave mode frequencies are measured using an all-optical pump-probe time-resolved magneto-optical Kerr-effect setup. Our studies address the problem of spin-wave confinement and spin-wave dipolar pinning in an array of coupled stripes. We show that the frequency of fundamental mode can be tuned to a large extent by adjusting the width of the stripes and the width of gaps between them.
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25
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Yoon J, Yang SH, Jeon JC, Migliorini A, Kostanovskiy I, Ma T, Parkin SSP. Local and global energy barriers for chiral domain walls in synthetic antiferromagnet-ferromagnet lateral junctions. Nat Nanotechnol 2022; 17:1183-1191. [PMID: 36203092 PMCID: PMC9646530 DOI: 10.1038/s41565-022-01215-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 08/17/2022] [Indexed: 06/16/2023]
Abstract
Of great promise are synthetic antiferromagnet-based racetrack devices in which chiral composite domain walls can be efficiently moved by current. However, overcoming the trade-off between energy efficiency and thermal stability remains a major challenge. Here we show that chiral domain walls in a synthetic antiferromagnet-ferromagnet lateral junction are highly stable against large magnetic fields, while the domain walls can be efficiently moved across the junction by current. Our approach takes advantage of field-induced global energy barriers in the unique energy landscape of the junction that are added to the local energy barrier. We demonstrate that thermal fluctuations are equivalent to the magnetic field effect, thereby, surprisingly, increasing the energy barrier and further stabilizing the domain wall in the junction at higher temperatures, which is in sharp contrast to ferromagnets or synthetic antiferromagnets. We find that the threshold current density can be further decreased by tilting the junction without affecting the high domain wall stability. Furthermore, we demonstrate that chiral domain walls can be robustly confined within a ferromagnet region sandwiched on both sides by synthetic antiferromagnets and yet can be readily injected into the synthetic antiferromagnet regions by current. Our findings break the aforementioned trade-off, thereby allowing for versatile domain-wall-based memory, and logic, and beyond.
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Affiliation(s)
- Jiho Yoon
- Max Planck Institute of Microstructure Physics, Halle, Germany
- Institute of Physics, Martin Luther University, Halle-Wittenberg, Halle, Germany
| | - See-Hun Yang
- Max Planck Institute of Microstructure Physics, Halle, Germany.
| | - Jae-Chun Jeon
- Max Planck Institute of Microstructure Physics, Halle, Germany
| | | | | | - Tianping Ma
- Max Planck Institute of Microstructure Physics, Halle, Germany
| | - Stuart S P Parkin
- Max Planck Institute of Microstructure Physics, Halle, Germany.
- Institute of Physics, Martin Luther University, Halle-Wittenberg, Halle, Germany.
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26
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Flores-Farías J, Gallardo RA, Brevis F, Roldán-Molina A, Cortés-Ortuño D, Landeros P. Omnidirectional flat bands in chiral magnonic crystals. Sci Rep 2022; 12:17831. [PMID: 36284121 DOI: 10.1038/s41598-022-20539-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 09/14/2022] [Indexed: 11/08/2022] Open
Abstract
The magnonic band structure of two-dimensional chiral magnonic crystals is theoretically investigated. The proposed metamaterial involves a three-dimensional architecture, where a thin ferromagnetic layer is in contact with a two-dimensional periodic array of heavy-metal square islands. When these two materials are in contact, an anti-symmetric exchange coupling known as the Dzyaloshinskii–Moriya interaction (DMI) arises, which generates nonreciprocal spin waves and chiral magnetic order. The Landau–Lifshitz equation and the plane-wave method are employed to study the dynamic magnetic behavior. A systematic variation of geometric parameters, the DMI constant, and the filling fraction allows the examination of spin-wave propagation features, such as the spatial profiles of the dynamic magnetization, the isofrequency contours, and group velocities. In this study, it is found that omnidirectional flat magnonic bands are induced by a sufficiently strong Dzyaloshinskii–Moriya interaction underneath the heavy-metal islands, where the spin excitations are active. The theoretical results were substantiated by micromagnetic simulations. These findings are relevant for envisioning applications associated with spin-wave-based logic devices, where the nonreciprocity and channeling of the spin waves are of fundamental and practical scientific interest.
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27
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Gu K, Guan Y, Hazra BK, Deniz H, Migliorini A, Zhang W, Parkin SSP. Three-dimensional racetrack memory devices designed from freestanding magnetic heterostructures. Nat Nanotechnol 2022; 17:1065-1071. [PMID: 36138201 PMCID: PMC9576586 DOI: 10.1038/s41565-022-01213-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 08/09/2022] [Indexed: 06/16/2023]
Abstract
The fabrication of three-dimensional nanostructures is key to the development of next-generation nanoelectronic devices with a low device footprint. Magnetic racetrack memory encodes data in a series of magnetic domain walls that are moved by current pulses along magnetic nanowires. To date, most studies have focused on two-dimensional racetracks. Here we introduce a lift-off and transfer method to fabricate three-dimensional racetracks from freestanding magnetic heterostructures grown on a water-soluble sacrificial release layer. First, we create two-dimensional racetracks from freestanding films transferred onto sapphire substrates and show that they have nearly identical characteristics compared with the films before transfer. Second, we design three-dimensional racetracks by covering protrusions patterned on a sapphire wafer with freestanding magnetic heterostructures. We demonstrate current-induced domain-wall motion for synthetic antiferromagnetic three-dimensional racetracks with protrusions of up to 900 nm in height. Freestanding magnetic layers, as demonstrated here, may enable future spintronic devices with high packing density and low energy consumption.
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Affiliation(s)
- Ke Gu
- Max Planck Institute of Microstructure Physics, Halle, Germany.
| | - Yicheng Guan
- Max Planck Institute of Microstructure Physics, Halle, Germany
| | | | - Hakan Deniz
- Max Planck Institute of Microstructure Physics, Halle, Germany
| | | | - Wenjie Zhang
- Max Planck Institute of Microstructure Physics, Halle, Germany
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28
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Wolf D, Schneider S, Rößler UK, Kovács A, Schmidt M, Dunin-Borkowski RE, Büchner B, Rellinghaus B, Lubk A. Unveiling the three-dimensional magnetic texture of skyrmion tubes. Nat Nanotechnol 2022; 17:250-255. [PMID: 34931032 PMCID: PMC8930765 DOI: 10.1038/s41565-021-01031-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 10/12/2021] [Indexed: 05/04/2023]
Abstract
Magnetic skyrmions are stable topological solitons with complex non-coplanar spin structures. Their nanoscopic size and the low electric currents required to control their motion has opened a new field of research, skyrmionics, that aims for the usage of skyrmions as information carriers. Further advances in skyrmionics call for a thorough understanding of their three-dimensional (3D) spin texture, skyrmion-skyrmion interactions and the coupling to surfaces and interfaces, which crucially affect skyrmion stability and mobility. Here, we quantitatively reconstruct the 3D magnetic texture of Bloch skyrmions with sub-10-nanometre resolution using holographic vector-field electron tomography. The reconstructed textures reveal local deviations from a homogeneous Bloch character within the skyrmion tubes, details of the collapse of the skyrmion texture at surfaces and a correlated modulation of the skyrmion tubes in FeGe along their tube axes. Additionally, we confirm the fundamental principles of skyrmion formation through an evaluation of the 3D magnetic energy density across these magnetic solitons.
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Affiliation(s)
- Daniel Wolf
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
| | - Sebastian Schneider
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
- Dresden Center for Nanoanalysis, cfaed, Technische Universität Dresden, Dresden, Germany
| | - Ulrich K Rößler
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
| | - András Kovács
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich, Germany
| | - Marcus Schmidt
- Department Chemical Metal Science, Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, Jülich, Germany
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany
- Institute of Solid State and Materials Physics, Technische Universität Dresden, Dresden, Germany
- Würzburg-Dresden Cluster of Excellence ct.qmat, Dresden, Germany
| | - Bernd Rellinghaus
- Dresden Center for Nanoanalysis, cfaed, Technische Universität Dresden, Dresden, Germany
| | - Axel Lubk
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, Dresden, Germany.
- Institute of Solid State and Materials Physics, Technische Universität Dresden, Dresden, Germany.
- Würzburg-Dresden Cluster of Excellence ct.qmat, Dresden, Germany.
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29
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Cheng X, Cheng Z, Wang C, Li M, Gu P, Yang S, Li Y, Watanabe K, Taniguchi T, Ji W, Dai L. Light helicity detector based on 2D magnetic semiconductor CrI 3. Nat Commun 2021; 12:6874. [PMID: 34824280 PMCID: PMC8617301 DOI: 10.1038/s41467-021-27218-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 11/06/2021] [Indexed: 11/09/2022] Open
Abstract
Two-dimensional magnetic semiconductors provide a platform for studying physical phenomena at atomically thin limit, and promise magneto-optoelectronic devices application. Here, we report light helicity detectors based on graphene-CrI3-graphene vdW heterostructures. We investigate the circularly polarized light excited current and reflective magnetic circular dichroism (RMCD) under various magnetic fields in both monolayer and multilayer CrI3 devices. The devices exhibit clear helicity-selective photoresponse behavior determined by the magnetic state of CrI3. We also find abnormal negative photocurrents at higher bias in both monolayer and multilayer CrI3. A possible explanation is proposed for this phenomenon. Our work reveals the interplay between magnetic and optoelectronic properties in CrI3 and paves the way to developing spin-optoelectronic devices.
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Affiliation(s)
- Xing Cheng
- State Key Lab for Artificial Microstructure & Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Zhixuan Cheng
- State Key Lab for Artificial Microstructure & Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Cong Wang
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China
| | - Minglai Li
- State Key Lab for Artificial Microstructure & Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Pingfan Gu
- State Key Lab for Artificial Microstructure & Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Shiqi Yang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Yanping Li
- State Key Lab for Artificial Microstructure & Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Kenji Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Wei Ji
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China
| | - Lun Dai
- State Key Lab for Artificial Microstructure & Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China.
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China.
- Peking University Yangtze Delta Institute of Optoelectronics, Beijing, 100871, China.
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30
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Bommanaboyena SP, Backes D, Veiga LSI, Dhesi SS, Niu YR, Sarpi B, Denneulin T, Kovács A, Mashoff T, Gomonay O, Sinova J, Everschor-Sitte K, Schönke D, Reeve RM, Kläui M, Elmers HJ, Jourdan M. Readout of an antiferromagnetic spintronics system by strong exchange coupling of Mn(2)Au and Permalloy. Nat Commun 2021; 12:6539. [PMID: 34764314 DOI: 10.1038/s41467-021-26892-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 10/22/2021] [Indexed: 11/09/2022] Open
Abstract
In antiferromagnetic spintronics, the read-out of the staggered magnetization or Néel vector is the key obstacle to harnessing the ultra-fast dynamics and stability of antiferromagnets for novel devices. Here, we demonstrate strong exchange coupling of Mn2Au, a unique metallic antiferromagnet that exhibits Néel spin-orbit torques, with thin ferromagnetic Permalloy layers. This allows us to benefit from the well-established read-out methods of ferromagnets, while the essential advantages of antiferromagnetic spintronics are only slightly diminished. We show one-to-one imprinting of the antiferromagnetic on the ferromagnetic domain pattern. Conversely, alignment of the Permalloy magnetization reorients the Mn2Au Néel vector, an effect, which can be restricted to large magnetic fields by tuning the ferromagnetic layer thickness. To understand the origin of the strong coupling, we carry out high resolution electron microscopy imaging and we find that our growth yields an interface with a well-defined morphology that leads to the strong exchange coupling.
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31
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Satchell N, Mitchell T, Shepley PM, Darwin E, Hickey BJ, Burnell G. Pt and CoB trilayer Josephson [Formula: see text] junctions with perpendicular magnetic anisotropy. Sci Rep 2021; 11:11173. [PMID: 34045523 PMCID: PMC8159980 DOI: 10.1038/s41598-021-90432-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 04/05/2021] [Indexed: 11/13/2022] Open
Abstract
We report on the electrical transport properties of Nb based Josephson junctions with Pt/Co[Formula: see text]B[Formula: see text]/Pt ferromagnetic barriers. The barriers exhibit perpendicular magnetic anisotropy, which has the main advantage for potential applications over magnetisation in-plane systems of not affecting the Fraunhofer response of the junction. In addition, we report that there is no magnetic dead layer at the Pt/Co[Formula: see text]B[Formula: see text] interfaces, allowing us to study barriers with ultra-thin Co[Formula: see text]B[Formula: see text]. In the junctions, we observe that the magnitude of the critical current oscillates with increasing thickness of the Co[Formula: see text]B[Formula: see text] strong ferromagnetic alloy layer. The oscillations are attributed to the ground state phase difference across the junctions being modified from zero to [Formula: see text]. The multiple oscillations in the thickness range [Formula: see text] nm suggests that we have access to the first zero-[Formula: see text] and [Formula: see text]-zero phase transitions. Our results fuel the development of low-temperature memory devices based on ferromagnetic Josephson junctions.
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Affiliation(s)
- N. Satchell
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
| | - T. Mitchell
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
| | - P. M. Shepley
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
| | - E. Darwin
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
| | - B. J. Hickey
- 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
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32
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Sharma R, Mishra R, Ngo T, Guo YX, Fukami S, Sato H, Ohno H, Yang H. Electrically connected spin-torque oscillators array for 2.4 GHz WiFi band transmission and energy harvesting. Nat Commun 2021; 12:2924. [PMID: 34006830 PMCID: PMC8131736 DOI: 10.1038/s41467-021-23181-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 04/20/2021] [Indexed: 12/28/2022] Open
Abstract
The mutual synchronization of spin-torque oscillators (STOs) is critical for communication, energy harvesting and neuromorphic applications. Short range magnetic coupling-based synchronization has spatial restrictions (few µm), whereas the long-range electrical synchronization using vortex STOs has limited frequency responses in hundreds MHz (<500 MHz), restricting them for on-chip GHz-range applications. Here, we demonstrate electrical synchronization of four non-vortex uniformly-magnetized STOs using a single common current source in both parallel and series configurations at 2.4 GHz band, resolving the frequency-area quandary for designing STO based on-chip communication systems. Under injection locking, synchronized STOs demonstrate an excellent time-domain stability and substantially improved phase noise performance. By integrating the electrically connected eight STOs, we demonstrate the battery-free energy-harvesting system by utilizing the wireless radio-frequency energy to power electronic devices such as LEDs. Our results highlight the significance of electrical topology (series vs. parallel) while designing an on-chip STOs system.
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Affiliation(s)
- Raghav Sharma
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Rahul Mishra
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
- Centre for Applied Research in Electronics, Indian Institute of Technology Delhi, New Delhi, India
| | - Tung Ngo
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Yong-Xin Guo
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Shunsuke Fukami
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba, Sendai, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, Aoba, Sendai, Japan
- Center for Spintronics Research Network, Tohoku University, Aoba, Sendai, Japan
- Center for Innovative Integrated Electronic Systems, Tohoku University, Sendai, Japan
- WPI Advanced Institute for Materials Research, Tohoku University, Aoba, Sendai, Japan
| | - Hideo Sato
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba, Sendai, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, Aoba, Sendai, Japan
- Center for Spintronics Research Network, Tohoku University, Aoba, Sendai, Japan
- Center for Innovative Integrated Electronic Systems, Tohoku University, Sendai, Japan
| | - Hideo Ohno
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba, Sendai, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, Aoba, Sendai, Japan
- Center for Spintronics Research Network, Tohoku University, Aoba, Sendai, Japan
- Center for Innovative Integrated Electronic Systems, Tohoku University, Sendai, Japan
- WPI Advanced Institute for Materials Research, Tohoku University, Aoba, Sendai, Japan
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
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33
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Qin H, Holländer RB, Flajšman L, Hermann F, Dreyer R, Woltersdorf G, van Dijken S. Nanoscale magnonic Fabry-Pérot resonator for low-loss spin-wave manipulation. Nat Commun 2021; 12:2293. [PMID: 33863877 PMCID: PMC8052321 DOI: 10.1038/s41467-021-22520-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 03/15/2021] [Indexed: 11/08/2022] Open
Abstract
Active control of propagating spin waves on the nanoscale is essential for beyond-CMOS magnonic computing. Here, we experimentally demonstrate reconfigurable spin-wave transport in a hybrid YIG-based material structure that operates as a Fabry-Pérot nanoresonator. The magnonic resonator is formed by a local frequency downshift of the spin-wave dispersion relation in a continuous YIG film caused by dynamic dipolar coupling to a ferromagnetic metal nanostripe. Drastic downscaling of the spin-wave wavelength within the bilayer region enables programmable control of propagating spin waves on a length scale that is only a fraction of their wavelength. Depending on the stripe width, the device structure offers full nonreciprocity, tunable spin-wave filtering, and nearly zero transmission loss at allowed frequencies. Our results provide a practical route for the implementation of low-loss YIG-based magnonic devices with controllable transport properties.
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Affiliation(s)
- Huajun Qin
- NanoSpin, Department of Applied Physics, Aalto University School of Science, Aalto, Finland.
| | - Rasmus B Holländer
- NanoSpin, Department of Applied Physics, Aalto University School of Science, Aalto, Finland
| | - Lukáš Flajšman
- NanoSpin, Department of Applied Physics, Aalto University School of Science, Aalto, Finland
| | - Felix Hermann
- NanoSpin, Department of Applied Physics, Aalto University School of Science, Aalto, Finland
- Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Rouven Dreyer
- Institute of Physics, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Georg Woltersdorf
- Institute of Physics, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Sebastiaan van Dijken
- NanoSpin, Department of Applied Physics, Aalto University School of Science, Aalto, Finland.
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34
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Fulara H, Zahedinejad M, Khymyn R, Dvornik M, Fukami S, Kanai S, Ohno H, Åkerman J. Giant voltage-controlled modulation of spin Hall nano-oscillator damping. Nat Commun 2020; 11:4006. [PMID: 32782243 PMCID: PMC7419544 DOI: 10.1038/s41467-020-17833-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 07/08/2020] [Indexed: 11/09/2022] Open
Abstract
Spin Hall nano-oscillators (SHNOs) are emerging spintronic devices for microwave signal generation and oscillator-based neuromorphic computing combining nano-scale footprint, fast and ultra-wide microwave frequency tunability, CMOS compatibility, and strong non-linear properties providing robust large-scale mutual synchronization in chains and two-dimensional arrays. While SHNOs can be tuned via magnetic fields and the drive current, neither approach is conducive to individual SHNO control in large arrays. Here, we demonstrate electrically gated W/CoFeB/MgO nano-constrictions in which the voltage-dependent perpendicular magnetic anisotropy tunes the frequency and, thanks to nano-constriction geometry, drastically modifies the spin-wave localization in the constriction region resulting in a giant 42% variation of the effective damping over four volts. As a consequence, the SHNO threshold current can be strongly tuned. Our demonstration adds key functionality to nano-constriction SHNOs and paves the way for energy-efficient control of individual oscillators in SHNO chains and arrays for neuromorphic computing.
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Affiliation(s)
- Himanshu Fulara
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden.
| | - Mohammad Zahedinejad
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
- NanOsc AB, Electrum 229, 164 40, Kista, Sweden
| | - Roman Khymyn
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - Mykola Dvornik
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
- NanOsc AB, Electrum 229, 164 40, Kista, Sweden
| | - Shunsuke Fukami
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
- Center for Spintronics Research Network, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
- Center for Innovative Integrated Electronic Systems, Tohoku University, 468-1 Aramaki Aza Aoba, Aoba-ku, Sendai, 980-0845, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
- WPI-Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Shun Kanai
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
- Center for Spintronics Research Network, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Hideo Ohno
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
- Center for Spintronics Research Network, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
- Center for Innovative Integrated Electronic Systems, Tohoku University, 468-1 Aramaki Aza Aoba, Aoba-ku, Sendai, 980-0845, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
- WPI-Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Johan Åkerman
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden.
- NanOsc AB, Electrum 229, 164 40, Kista, Sweden.
- Material and Nanophysics, School of Engineering Sciences, KTH Royal Institute of Technology, Electrum 229, 164 40, Kista, Sweden.
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Karwacki Ł, Grochot K, Łazarski S, Skowroński W, Kanak J, Powroźnik W, Barnaś J, Stobiecki F, Stobiecki T. Optimization of spin Hall magnetoresistance in heavy-metal/ferromagnetic-metal bilayers. Sci Rep 2020; 10:10767. [PMID: 32612163 PMCID: PMC7329912 DOI: 10.1038/s41598-020-67450-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 06/08/2020] [Indexed: 11/22/2022] Open
Abstract
We present experimental data and their theoretical description on spin Hall magnetoresistance (SMR) in bilayers consisting of a heavy metal (H) coupled to in-plane magnetized ferromagnetic metal (F), and determine contributions to the magnetoresistance due to SMR and anisotropic magnetoresistance (AMR) in five different bilayer systems: [Formula: see text], [Formula: see text], [Formula: see text], W/Co, and Co/Pt. The devices used for experiments have different interfacial properties due to either amorphous or crystalline structures of constitutent layers. To determine magnetoresistance contributions and to allow for optimization, the AMR is explicitly included in the diffusion transport equations in the ferromagnets. The results allow determination of different contributions to the magnetoresistance, which can play an important role in optimizing prospective magnetic stray field sensors. They also may be useful in the determination of spin transport properties of metallic magnetic heterostructures in other experiments based on magnetoresistance measurements.
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Affiliation(s)
- Łukasz Karwacki
- Institute of Molecular Physics, Polish Academy of Sciences, ul. M. Smoluchowskiego 17, 60-179, Poznań, Poland.
- Department of Electronics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059, Kraków, Poland.
| | - Krzysztof Grochot
- Department of Electronics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059, Kraków, Poland.
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059, Kraków, Poland.
| | - Stanisław Łazarski
- Department of Electronics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059, Kraków, Poland
| | - Witold Skowroński
- Department of Electronics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059, Kraków, Poland
| | - Jarosław Kanak
- Department of Electronics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059, Kraków, Poland
| | - Wiesław Powroźnik
- Department of Electronics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059, Kraków, Poland
| | - Józef Barnaś
- Institute of Molecular Physics, Polish Academy of Sciences, ul. M. Smoluchowskiego 17, 60-179, Poznań, Poland
- Faculty of Physics, Adam Mickiewicz University, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznań, Poland
| | - Feliks Stobiecki
- Institute of Molecular Physics, Polish Academy of Sciences, ul. M. Smoluchowskiego 17, 60-179, Poznań, Poland
| | - Tomasz Stobiecki
- Department of Electronics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059, Kraków, Poland
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059, Kraków, Poland
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36
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Tu S, Ziman T, Yu G, Wan C, Hu J, Wu H, Wang H, Liu M, Liu C, Guo C, Zhang J, Cabero Z MA, Zhang Y, Gao P, Liu S, Yu D, Han X, Hallsteinsen I, Gilbert DA, Matsuo M, Ohnuma Y, Wölfle P, Wang KL, Ansermet JP, Maekawa S, Yu H. Record thermopower found in an IrMn-based spintronic stack. Nat Commun 2020; 11:2023. [PMID: 32332726 PMCID: PMC7181642 DOI: 10.1038/s41467-020-15797-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 03/25/2020] [Indexed: 11/25/2022] Open
Abstract
The Seebeck effect converts thermal gradients into electricity. As an approach to power technologies in the current Internet-of-Things era, on-chip energy harvesting is highly attractive, and to be effective, demands thin film materials with large Seebeck coefficients. In spintronics, the antiferromagnetic metal IrMn has been used as the pinning layer in magnetic tunnel junctions that form building blocks for magnetic random access memories and magnetic sensors. Spin pumping experiments revealed that IrMn Néel temperature is thickness-dependent and approaches room temperature when the layer is thin. Here, we report that the Seebeck coefficient is maximum at the Néel temperature of IrMn of 0.6 to 4.0 nm in thickness in IrMn-based half magnetic tunnel junctions. We obtain a record Seebeck coefficient 390 (±10) μV K-1 at room temperature. Our results demonstrate that IrMn-based magnetic devices could harvest the heat dissipation for magnetic sensors, thus contributing to the Power-of-Things paradigm.
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Affiliation(s)
- Sa Tu
- Fert Beijing Institute, BDBC, School of Microelectronics, Beihang University, 100191, Beijing, China
| | - Timothy Ziman
- Institut Laue-Langevin, 38042, Grenoble, France
- Université de Grenobles-Alpes, and CNRS, LPMMC, 38042, Grenoble, France
- Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Guoqiang Yu
- Department of Electrical Engineering, University of California, Los Angeles, CA, 90095, USA
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 100190, Beijing, China
| | - Caihua Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 100190, Beijing, China
| | - Junfeng Hu
- Fert Beijing Institute, BDBC, School of Microelectronics, Beihang University, 100191, Beijing, China
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Hao Wu
- Department of Electrical Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Hanchen Wang
- Fert Beijing Institute, BDBC, School of Microelectronics, Beihang University, 100191, Beijing, China
| | - Mengchao Liu
- Electron Microscopy Laboratory, School of Physics, Peking University, 100871, Beijing, China
| | - Chuanpu Liu
- Fert Beijing Institute, BDBC, School of Microelectronics, Beihang University, 100191, Beijing, China
| | - Chenyang Guo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 100190, Beijing, China
| | - Jianyu Zhang
- Fert Beijing Institute, BDBC, School of Microelectronics, Beihang University, 100191, Beijing, China
| | - Marco A Cabero Z
- Fert Beijing Institute, BDBC, School of Microelectronics, Beihang University, 100191, Beijing, China
- Shenzhen Institute for Quantum Science and Engineering (SIQSE), and Department of Physics, Southern University of Science and Technology (SUSTech), 518055, Shenzhen, China
| | - Youguang Zhang
- Fert Beijing Institute, BDBC, School of Microelectronics, Beihang University, 100191, Beijing, China
| | - Peng Gao
- Electron Microscopy Laboratory, School of Physics, Peking University, 100871, Beijing, China
- International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China
- Collaborative Innovation Center of Quantum Matter, 100871, Beijing, China
| | - Song Liu
- Shenzhen Institute for Quantum Science and Engineering (SIQSE), and Department of Physics, Southern University of Science and Technology (SUSTech), 518055, Shenzhen, China
| | - Dapeng Yu
- Electron Microscopy Laboratory, School of Physics, Peking University, 100871, Beijing, China
- Shenzhen Institute for Quantum Science and Engineering (SIQSE), and Department of Physics, Southern University of Science and Technology (SUSTech), 518055, Shenzhen, China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 100190, Beijing, China
| | - Ingrid Hallsteinsen
- Department of Electronic Systems, Norwegian University of Science and Technology, Trondheim, 7491, Norway
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Dustin A Gilbert
- Material Science and Engineering Department, University of Tennessee, Knoxville, TN, 37996, USA
| | - Mamoru Matsuo
- Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Yuichi Ohnuma
- Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Peter Wölfle
- Institute for Theory of Condensed Matter, Karlsruhe Institute of Technology, 76049, Karlsruhe, Germany
| | - Kang L Wang
- Department of Electrical Engineering, University of California, Los Angeles, CA, 90095, USA
| | - Jean-Philippe Ansermet
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Sadamichi Maekawa
- Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, 100190, Beijing, China
- RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan
| | - Haiming Yu
- Fert Beijing Institute, BDBC, School of Microelectronics, Beihang University, 100191, Beijing, China.
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37
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Avilés-Félix L, Olivier A, Li G, Davies CS, Álvaro-Gómez L, Rubio-Roy M, Auffret S, Kirilyuk A, Kimel AV, Rasing T, Buda-Prejbeanu LD, Sousa RC, Dieny B, Prejbeanu IL. Single-shot all-optical switching of magnetization in Tb/Co multilayer-based electrodes. Sci Rep 2020; 10:5211. [PMID: 32251329 PMCID: PMC7089968 DOI: 10.1038/s41598-020-62104-w] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 03/06/2020] [Indexed: 11/10/2022] Open
Abstract
Ever since the first observation of all-optical switching of magnetization in the ferrimagnetic alloy GdFeCo using femtosecond laser pulses, there has been significant interest in exploiting this process for data-recording applications. In particular, the ultrafast speed of the magnetic reversal can enable the writing speeds associated with magnetic memory devices to be potentially pushed towards THz frequencies. This work reports the development of perpendicular magnetic tunnel junctions incorporating a stack of Tb/Co nanolayers whose magnetization can be all-optically controlled via helicity-independent single-shot switching. Toggling of the magnetization of the Tb/Co electrode was achieved using either 60 femtosecond-long or 5 picosecond-long laser pulses, with incident fluences down to 3.5 mJ/cm2, for Co-rich compositions of the stack either in isolation or coupled to a CoFeB-electrode/MgO-barrier tunnel-junction stack. Successful switching of the CoFeB-[Tb/Co] electrodes was obtained even after annealing at 250 °C. After integration of the [Tb/Co]-based electrodes within perpendicular magnetic tunnel junctions yielded a maximum tunneling magnetoresistance signal of 41% and RxA value of 150 Ωμm2 with current-in-plane measurements and ratios between 28% and 38% in nanopatterned pillars. These results represent a breakthrough for the development of perpendicular magnetic tunnel junctions controllable using single laser pulses, and offer a technologically-viable path towards the realization of hybrid spintronic-photonic systems featuring THz switching speeds.
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Affiliation(s)
- L Avilés-Félix
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France.
| | - A Olivier
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - G Li
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525, AJ Nijmegen, The Netherlands
| | - C S Davies
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525, AJ Nijmegen, The Netherlands
- FELIX Laboratory, Radboud University, 7 Toernooiveld, 6525, ED Nijmegen, The Netherlands
| | - L Álvaro-Gómez
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - M Rubio-Roy
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - S Auffret
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - A Kirilyuk
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525, AJ Nijmegen, The Netherlands
- FELIX Laboratory, Radboud University, 7 Toernooiveld, 6525, ED Nijmegen, The Netherlands
| | - A V Kimel
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525, AJ Nijmegen, The Netherlands
| | - Th Rasing
- Radboud University, Institute for Molecules and Materials, Heyendaalseweg 135, 6525, AJ Nijmegen, The Netherlands
| | - L D Buda-Prejbeanu
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - R C Sousa
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - B Dieny
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
| | - I L Prejbeanu
- Spintec, Université Grenoble Alpes, CNRS, CEA, Grenoble INP, IRIG-SPINTEC, 38000, Grenoble, France
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38
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Hou J, Wang Y, Eguchi K, Nanjo C, Takaoka T, Sainoo Y, Arafune R, Awaga K, Komeda T. Enhanced magnetic spin-spin interactions observed between porphyrazine derivatives on Au(111). Commun Chem 2020; 3:36. [PMID: 36703412 DOI: 10.1038/s42004-020-0282-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 02/28/2020] [Indexed: 01/29/2023] Open
Abstract
Magnetic molecules are of interest for application in spintronic and quantum-information processing devices. Therein, control of the interaction between the spins of neighboring molecules is the critical issue. Substitution of outer moieties of the molecule can tune the molecule-molecule interaction. Here we show a novel spin behavior for a magnetic molecule of vanadyl tetrakis (thiadiazole) porphyrazine (abbreviated as VOTTDPz) adsorbed on Au(111), which is modified from vanadyl phthalocyanine (VOPc) by replacing the inert phthalocyanine ligand with a reactive thiadiazole moiety. The magnetic properties of the molecules are examined by observing the Kondo resonance caused by the screening of an isolated spin by conduction electrons using scanning tunneling spectroscopy. The Kondo features are detected at the molecule whose shape and intensity show site-dependent variation, revealing complex spin-spin interactions due to the enhanced interaction between molecules, originating from the functionalization of the ligand with a more reactive moiety.
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39
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Au TH, Perry A, Audibert J, Trinh DT, Do DB, Buil S, Quélin X, Hermier JP, Lai ND. Controllable movement of single-photon source in multifunctional magneto-photonic structures. Sci Rep 2020; 10:4843. [PMID: 32179841 PMCID: PMC7075966 DOI: 10.1038/s41598-020-61811-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 03/02/2020] [Indexed: 11/09/2022] Open
Abstract
Quantum dot (QD) coupling in nanophotonics has been widely studied for various potential applications in quantum technologies. Micro-machining has also attracted substantial research interest due to its capacity to use miniature robotic tools to make precise controlled movements. In this work, we combine fluorescent QDs and magnetic nanoparticles (NPs) to realize multifunctional microrobotic structures and demonstrate the manipulation of a coupled single-photon source (SPS) in 3D space via an external magnetic field. By employing the low one photon absorption (LOPA) direct laser writing (DLW) technique, the fabrication of 2D and 3D magneto-photonic devices containing a single QD is performed on a hybrid material consisting of colloidal CdSe/CdS QDs, magnetite Fe3O4 NPs, and SU-8 photoresist. Two types of devices, contact-free and in-contact structures, are investigated to demonstrate their magnetic and photoradiative responses. The coupled SPS in the devices is driven by the external magnetic field to perform different movements in a 3D fluidic environment. The optical properties of the single QD in the devices are characterized.
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Affiliation(s)
- Thi Huong Au
- Laboratoire Lumière, Matière et Interfaces, FRE 2036, École Normale Supérieure Paris-Saclay, Centrale Supélec, CNRS, Université Paris-Saclay, 4 Avenue des Sciences, 91190, Gif-sur-Yvette, France
- Groupe d'étude de la matière condensée, Université Paris-Saclay, UVSQ, CNRS, 45 Avenue des États-Unis, 78035, Versailles, France
| | - Amber Perry
- Laboratoire Lumière, Matière et Interfaces, FRE 2036, École Normale Supérieure Paris-Saclay, Centrale Supélec, CNRS, Université Paris-Saclay, 4 Avenue des Sciences, 91190, Gif-sur-Yvette, France
- Lewis & Clark College, 0615 SW Palatine Hill Rd, Portland, OR, 97219, USA
| | - Jeff Audibert
- Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires, UMR 8531, École Normale Supérieure Paris-Saclay, CNRS, Université Paris-Saclay, 4 Avenue des Sciences, 91190, Gif-sur-Yvette, France
| | - Duc Thien Trinh
- Faculty of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, 100000, Hanoi, Vietnam
| | - Danh Bich Do
- Faculty of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, 100000, Hanoi, Vietnam
| | - Stéphanie Buil
- Groupe d'étude de la matière condensée, Université Paris-Saclay, UVSQ, CNRS, 45 Avenue des États-Unis, 78035, Versailles, France
| | - Xavier Quélin
- Groupe d'étude de la matière condensée, Université Paris-Saclay, UVSQ, CNRS, 45 Avenue des États-Unis, 78035, Versailles, France
| | - Jean-Pierre Hermier
- Groupe d'étude de la matière condensée, Université Paris-Saclay, UVSQ, CNRS, 45 Avenue des États-Unis, 78035, Versailles, France.
| | - Ngoc Diep Lai
- Laboratoire Lumière, Matière et Interfaces, FRE 2036, École Normale Supérieure Paris-Saclay, Centrale Supélec, CNRS, Université Paris-Saclay, 4 Avenue des Sciences, 91190, Gif-sur-Yvette, France.
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40
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Abstract
The paper presents our simulated results showing the substantial improvement of both switching speed and energy consumption in a perpendicular magnetic tunnel junction (p-MTJ), a core unit of Spin-Transfer-Torque Magnetic Random Access Memory (STT-MRAM), by the help of additional Spin-Orbit-Torque (SOT) write pulse current (WPSOT). An STT-SOT hybrid torque module for OOMMF simulation is implemented to investigate the switching behavior of a 20 nm cell in the p-MTJ. We found that the assistance of WPSOT to STT write pulse current (WPSTT) have a huge influence on the switching behavior of the free layer in the p-MTJ. For example, we could dramatically reduce the switching time (tSW) by 80% and thereby reduce the write energy over 70% as compared to those in the absence of the WPSOT. Even a very tiny amplitude of WPSOT (JSOT of the order of 102 A/m2) substantially assists to reduce the critical current density for switching of the free layer and thereby decreases the energy consumption as well. It is worth to be pointed out that the energy can be saved further by tuning the WPSOT parameters, i.e., amplitude and duration along at the threshold WPSTT. Our findings show that the proposed STT-SOT hybrid switching scheme has a great impact on the MRAM technology seeking the high speed and low energy consumption.
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Affiliation(s)
- Sachin Pathak
- Materials Science and Engineering, Yonsei University, Seoul, 03722, Korea
- Physics, University of Petroleum and Energy Studies, Dehradun, 248007, India
| | - Chanyoung Youm
- Materials Science and Engineering, Yonsei University, Seoul, 03722, Korea
| | - Jongill Hong
- Materials Science and Engineering, Yonsei University, Seoul, 03722, Korea.
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41
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Abstract
In ferromagnetic trilayers, a spin-orbit-induced spin current can have a spin polarization of which direction is deviated from that for the spin Hall effect. Recently, magnetization switching in ferromagnetic trilayers has been proposed and confirmed by the experiments. In this work, we theoretically and numerically investigate the switching current required for perpendicular magnetization switching in ferromagnetic trilayers. We confirm that the tilted spin polarization enables field-free deterministic switching at a lower current than conventional spin-orbit torque or spin-transfer torque switching, offering a possibility for high-density and low-power spin-orbit torque devices. Moreover, we provide analytical expressions of the switching current for an arbitrary spin polarization direction, which will be useful to design spin-orbit torque devices and to interpret spin-orbit torque switching experiments.
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Affiliation(s)
- Dong-Kyu Lee
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, Korea
| | - Kyung-Jin Lee
- Department of Materials Science and Engineering, Korea University, Seoul, 02841, Korea.
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Korea.
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42
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Vélez S, Schaab J, Wörnle MS, Müller M, Gradauskaite E, Welter P, Gutgsell C, Nistor C, Degen CL, Trassin M, Fiebig M, Gambardella P. High-speed domain wall racetracks in a magnetic insulator. Nat Commun 2019; 10:4750. [PMID: 31628309 PMCID: PMC6802104 DOI: 10.1038/s41467-019-12676-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 09/23/2019] [Indexed: 11/21/2022] Open
Abstract
Recent reports of current-induced switching of ferrimagnetic oxides coupled to heavy metals have opened prospects for implementing magnetic insulators into electrically addressable devices. However, the configuration and dynamics of magnetic domain walls driven by electrical currents in insulating oxides remain unexplored. Here we investigate the internal structure of the domain walls in Tm3Fe5O12 (TmIG) and TmIG/Pt bilayers, and demonstrate their efficient manipulation by spin-orbit torques with velocities of up to 400 ms-1 and minimal current threshold for domain wall flow of 5 × 106 A cm-2. Domain wall racetracks are defined by Pt current lines on continuous TmIG films, which allows for patterning the magnetic landscape of TmIG in a fast and reversible way. Scanning nitrogen-vacancy magnetometry reveals that the domain walls of TmIG thin films grown on Gd3Sc2Ga3O12 exhibit left-handed Néel chirality, changing to an intermediate Néel-Bloch configuration upon Pt deposition. These results indicate the presence of interfacial Dzyaloshinskii-Moriya interaction in magnetic garnets, opening the possibility to stabilize chiral spin textures in centrosymmetric magnetic insulators.
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Affiliation(s)
- Saül Vélez
- Department of Materials, ETH Zurich, 8093, Zurich, Switzerland.
| | - Jakob Schaab
- Department of Materials, ETH Zurich, 8093, Zurich, Switzerland
| | - Martin S Wörnle
- Department of Materials, ETH Zurich, 8093, Zurich, Switzerland
- Department of Physics, ETH Zurich, 8093, Zurich, Switzerland
| | - Marvin Müller
- Department of Materials, ETH Zurich, 8093, Zurich, Switzerland
| | | | - Pol Welter
- Department of Physics, ETH Zurich, 8093, Zurich, Switzerland
| | | | - Corneliu Nistor
- Department of Materials, ETH Zurich, 8093, Zurich, Switzerland
| | | | - Morgan Trassin
- Department of Materials, ETH Zurich, 8093, Zurich, Switzerland.
| | - Manfred Fiebig
- Department of Materials, ETH Zurich, 8093, Zurich, Switzerland.
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43
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Gómez-Pastora J, Karampelas IH, Bringas E, Furlani EP, Ortiz I. Numerical Analysis of Bead Magnetophoresis from Flowing Blood in a Continuous-Flow Microchannel: Implications to the Bead-Fluid Interactions. Sci Rep 2019; 9:7265. [PMID: 31086252 PMCID: PMC6514169 DOI: 10.1038/s41598-019-43827-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 04/30/2019] [Indexed: 01/08/2023] Open
Abstract
In this work, we report a numerical flow-focused study of bead magnetophoresis inside a continuous-flow microchannel in order to provide a detailed analysis of bead motion and its effect on fluid flow. The numerical model involves a Lagrangian approach and predicts the bead separation from blood and their collection into a flowing buffer by the application of a magnetic field generated by a permanent magnet. The following scenarios are modelled: (i) one-way coupling wherein momentum is transferred from the fluid to beads, which are treated as point particles, (ii) two-way coupling wherein the beads are treated as point particles and momentum is transferred from the bead to the fluid and vice versa, and (iii) two-way coupling taking into account the effects of bead volume in fluid displacement. The results indicate that although there is little difference in the bead trajectories for the three scenarios, there is significant variation in the flow fields, especially when high magnetic forces are applied on the beads. Therefore, an accurate full flow-focused model that takes into account the effects of the bead motion and volume on the flow field should be solved when high magnetic forces are employed. Nonetheless, when the beads are subjected to medium or low magnetic forces, computationally inexpensive models can be safely employed to model magnetophoresis.
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Affiliation(s)
- Jenifer Gómez-Pastora
- Department of Chemical and Biomolecular Engineering, ETSIIT, University of Cantabria, Avda. Los Castros s/n, 39005, Santander, Spain
| | | | - Eugenio Bringas
- Department of Chemical and Biomolecular Engineering, ETSIIT, University of Cantabria, Avda. Los Castros s/n, 39005, Santander, Spain
| | - Edward P Furlani
- Department of Chemical and Biological Engineering, University at Buffalo (SUNY), Buffalo, New York, 14260, USA
- Department of Electrical Engineering, University at Buffalo (SUNY), Buffalo, New York, 14260, USA
| | - Inmaculada Ortiz
- Department of Chemical and Biomolecular Engineering, ETSIIT, University of Cantabria, Avda. Los Castros s/n, 39005, Santander, Spain.
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44
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Hajiaghajani A, Ahn S. Single-Sided Near-Field Wireless Power Transfer by A Three-Dimensional Coil Array. Micromachines (Basel) 2019; 10:mi10030200. [PMID: 30901921 PMCID: PMC6471491 DOI: 10.3390/mi10030200] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 03/08/2019] [Accepted: 03/19/2019] [Indexed: 12/05/2022]
Abstract
Wirelessly powered medical microrobots are often driven or localized by magnetic resonance imaging coils, whose signal-to-noise ratio is easily affected by the power transmitter coils that supply the microrobot. A controlled single-sided wireless power transmitter can enhance the imaging quality and suppress the radiation leakage. This paper presents a new form of electromagnet which automatically cancels the magnetic field to the back lobes by replacing the traditional circular coils with a three-dimensional (3D) coil scheme inspired by a generalized form of Halbach arrays. It is shown that, along with the miniaturization of the transmitter system, it allows for improved magnetic field intensity in the target side. Measurement of the produced magnetic patterns verifies that the power transfer to the back lobe is 15-fold smaller compared to the corresponding distance on the main lobe side, whilst maintaining a powering efficiency similar to that of conventional planar coils. To show the application of the proposed array, a wireless charging pad with an effective powering area of 144 cm2 is fabricated on 3D-assembled printed circuit boards. This 3D structure obviates the need for traditional magnetic shield materials that place limitations on the working frequency and suffer from non-linearity and hysteresis effects.
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Affiliation(s)
- Amirhossein Hajiaghajani
- Department of Electrical Engineering and Computer Science, University of California, Irvine, CA 92697, USA.
| | - Seungyoung Ahn
- CCS Graduate School for Green Transportation, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
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45
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Ooi C, Earhart CM, Wilson RJ, Wang SX. Rapid Characterization of Magnetic Moment of Cells for Magnetic Separation. IEEE Trans Magn 2013; 49:3434-3437. [PMID: 24771946 PMCID: PMC3996843 DOI: 10.1109/tmag.2013.2245310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
NCI-H1650 lung cancer cell lines labeled with magnetic nanoparticles via the Epithelial Cell Adhesion Molecule (EpCAM) antigen were previously shown to be captured at high efficiencies by a microfabricated magnetic sifter. If fine control and optimization of the magnetic separation process is to be achieved, it is vital to be able to characterize the labeled cells' magnetic moment rapidly. We have thus adapted a rapid prototyping method to obtain the saturation magnetic moment of these cells. This method utilizes a cross-correlation algorithm to analyze the cells' motion in a simple fluidic channel to obtain their magnetophoretic velocity, and is effective even when the magnetic moments of cells are small. This rapid characterization is proven useful in optimizing our microfabricated magnetic sifter procedures for magnetic cell capture.
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Affiliation(s)
- Chinchun Ooi
- Chemical Engineering Department, Stanford University, Stanford, CA 94305 USA
| | - Christopher M Earhart
- Materials Science and Engineering Department, Stanford University, Stanford, CA 94305 USA
| | - Robert J Wilson
- Materials Science and Engineering Department, Stanford University, Stanford, CA 94305 USA
| | - Shan X Wang
- Materials Science and Engineering Department, Stanford University, Stanford, CA 94305 USA ; Electrical Engineering Department, Stanford University, Stanford, CA 94305 USA
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46
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Ooi C, Earhart CM, Wilson RJ, Wang SX. Effect of Magnetic Field Gradient on Effectiveness of the Magnetic Sifter for Cell Purification. IEEE Trans Magn 2013; 49:316-320. [PMID: 23515873 PMCID: PMC3600415 DOI: 10.1109/tmag.2012.2224851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In our experiments with NCI-H1650 lung cancer cell lines labeled with magnetic nanoparticles via the Epithelial Cell Adhesion Molecule (EpCAM) antigen, we demonstrate capture efficiencies above 90% even at sample flow rates of 5 ml/h through our microfabricated magnetic sifter. We also improve the elution efficiencies from between 50% and 60% to close to 90% via optimization of the permanent magnet size and position used to magnetize the sifter. We then explain our observations via the use of finite element software for magnetic field and field gradient distributions, and a particle tracing algorithm, illustrating the impact of magnetic field gradients on the performance of the magnetic sifter. The high capture and elution efficiencies observed here is especially significant for magnetic separation of biologically interesting but rare moieties such as cancer stem cells for downstream analysis.
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Affiliation(s)
- Chinchun Ooi
- Chemical Engineering Department, Stanford University, Stanford, CA 94305 USA
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47
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Sanz R, Fernández AB, Dominguez JA, Martín B, Michelena MD. Gamma irradiation of magnetoresistive sensors for planetary exploration. Sensors (Basel) 2012; 12:4447-65. [PMID: 22666039 PMCID: PMC3355420 DOI: 10.3390/s120404447] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 03/12/2012] [Accepted: 03/19/2012] [Indexed: 11/16/2022]
Abstract
A limited number of Anisotropic Magnetoresistive (AMR) commercial-off-the-shelf (COTS) magnetic sensors of the HMC series by Honeywell, with and without integrated front-end electronics, were irradiated with gamma rays up to a total irradiation dose of 200 krad (Si), following the ESCC Basic Specification No. 22900. Due to the magnetic cleanliness required for these tests a special set-up was designed and successfully employed. Several parameters of the sensors were monitored during testing and the results are reported in this paper. The authors conclude that AMR sensors without front-end electronics seem to be robust against radiation doses of up to 200 krad (Si) with a dose rate of 5 krad (Si)/hour and up to a resolution of tens of nT, but sensors with an integrated front-end seem to be more vulnerable to radiation.
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Affiliation(s)
- Ruy Sanz
- Space Programs & Space Sciences Department of the Spanish National Institute of Aerospace Technology (INTA), Madrid, Spain.
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