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Kurokawa Y, Yamada K, Taniguchi T, Horiike S, Tanaka T, Yuasa H. Ultra-wide-band millimeter-wave generator using spin torque oscillator with strong interlayer exchange couplings. Sci Rep 2022; 12:10849. [PMID: 35854024 PMCID: PMC9296563 DOI: 10.1038/s41598-022-15014-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 06/16/2022] [Indexed: 11/10/2022] Open
Abstract
Recent increased development interest in millimeter-wave oscillator devices has necessitated realization of small oscillators with high frequency, wide frequency tunability, and room-temperature operation. Spin-torque oscillators (STOs) are fascinating candidates for such applications because of their nanometer size and suitability for room-temperature operation. However, their oscillation frequency and tunable range are limited to the order of 100 MHz–10 GHz. Here, we propose use of bilinear (J1) and biquadratic (J2) interlayer exchange couplings between ferromagnets in STOs to overcome these problems. The bilinear coupling contributes to oscillation frequency enhancement, whereas the biquadratic coupling facilitates frequency tunability via a current. Using micromagnetic simulation with parameters estimated from a material with small saturation magnetization, for J1 = 0 and J2 = − 1.0 mJ/m2, respectively, we find that the STO exhibits high frequency from 23 to 576 GHz and that its tunability reaches 61 GHz/(1011 A/m2) for current densities of − 0.5 to − 9.5 × 1011 A/m2. An analytical theory based on the macrospin model is also developed, which exhibits good quantitative agreement with the micromagnetic simulations. These results introduce new possibilities for spintronics applications in high-frequency devices such as next-generation mobile communications.
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Affiliation(s)
- Yuichiro Kurokawa
- Graduate School and Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, 819-0395, Japan.
| | - Keisuke Yamada
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Gifu, 501-1193, Japan.
| | - Tomohiro Taniguchi
- Research Center for Emerging Computing Technologies, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan.
| | - Shu Horiike
- Graduate School and Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, 819-0395, Japan
| | - Terumitsu Tanaka
- Graduate School and Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, 819-0395, Japan
| | - Hiromi Yuasa
- Graduate School and Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, 819-0395, Japan
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2
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Banuazizi SAH, Houshang A, Awad AA, Mohammadi J, Åkerman J, Belova LM. Magnetic force microscopy of an operational spin nano-oscillator. MICROSYSTEMS & NANOENGINEERING 2022; 8:65. [PMID: 35721373 PMCID: PMC9200774 DOI: 10.1038/s41378-022-00380-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/05/2022] [Accepted: 03/04/2022] [Indexed: 06/15/2023]
Abstract
Magnetic force microscopy (MFM) is a powerful technique for studying magnetic microstructures and nanostructures that relies on force detection by a cantilever with a magnetic tip. The detected magnetic tip interactions are used to reconstruct the magnetic structure of the sample surface. Here, we demonstrate a new method using MFM for probing the spatial profile of an operational nanoscale spintronic device, the spin Hall nano-oscillator (SHNO), which generates high-intensity spin wave auto-oscillations enabling novel microwave applications in magnonics and neuromorphic computing. We developed an MFM system by adding a microwave probe station to allow electrical and microwave characterization up to 40 GHz during the MFM process. SHNOs-based on NiFe/Pt bilayers with a specific design compatible with the developed system-were fabricated and scanned using a Co magnetic force microscopy tip with 10 nm spatial MFM resolution, while a DC current sufficient to induce auto-oscillation flowed. Our results show that this developed method provides a promising path for the characterization and nanoscale magnetic field imaging of operational nano-oscillators.
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Affiliation(s)
- Seyed Amir Hossein Banuazizi
- Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
- Materials and Nanophysics, Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 114 19 Stockholm, Sweden
| | - Afshin Houshang
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
| | - Ahmad A. Awad
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
| | - Javad Mohammadi
- Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | - Johan Åkerman
- Materials and Nanophysics, Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, 114 19 Stockholm, Sweden
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
| | - Liubov M. Belova
- Department of Materials Science and Engineering, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
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3
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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] [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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4
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Zeng L, Liu Y, Chen HH, Zhou Y, Zhang D, Zhang Y, Zhao W. Robust phase shift keying modulation method for spin torque nano-oscillator. NANOTECHNOLOGY 2020; 31:375205. [PMID: 32396892 DOI: 10.1088/1361-6528/ab925a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The spin torque nano-oscillator (STNO) is a very promising candidate for next generation telecommunication systems due to its small size ~100 nm and high output frequency range. However, it still suffers low output power, usually smaller than µW, and very high phase noise. Also, the modulation method for the STNO should be further developed. The frequency modulation and amplitude modulation method for STNO can be easily applied because of the non-linear nature of STNO, yet it is very rare to see the proposal of a phase modulation method. In this work, we propose a robust phase shift keying modulation method for STNO. Its feasibility is demonstrated with both theoretical and numerical analysis, and its robustness is investigated under room temperature thermal noise. It is shown that our proposed phase modulation method can tune the phase arbitrarily, while the modulation speed can be as fast as 10 ns at room temperature. Comparing with the other phase modulation method, our approach has advantages of larger phase tuning range and stronger robustness against thermal noise.
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Affiliation(s)
- Lang Zeng
- Fert Beijing Institute, BDBC, and School of Microelectronics, Beihang University, Beijing 100191, People's Republic of China. Hefei Innovation Research Institute, Beihang University, Hefei 230013, People's Republic of China
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5
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Whang HS, Choe SB. Spin-Hall-effect-modulation skyrmion oscillator. Sci Rep 2020; 10:11977. [PMID: 32686732 PMCID: PMC7371710 DOI: 10.1038/s41598-020-68710-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/05/2020] [Indexed: 11/15/2022] Open
Abstract
The electric-current-induced spin torque on local magnetization allows the electric control of magnetization, leading to numerous key concepts of spintronic devices. Utilizing the steady-state spin precession under spin-polarized current, a nanoscale spin-torque oscillator tunable over GHz range is one of those promising concepts. Albeit successful proof of principles to date, the spin-torque oscillators still suffer from issues regarding output power, linewidth and magnetic-field-free operation. Here we propose an entirely new concept of spin-torque oscillator, based on magnetic skyrmion dynamics subject to lateral modulation of the spin-Hall effect (SHE). In the oscillator, a skyrmion circulates around the modulation boundary between opposite SHE-torque regions, since the SHE pushes the skyrmion toward the modulation boundary in both regions. A micromagnetic simulation confirmed such oscillations with frequencies of up to 15 GHz in media composed of synthetic ferrimagnets. This fast and robust SHE-modulation-based skyrmion oscillator is expected to overcome the issues associated with conventional spin-torque oscillators.
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Affiliation(s)
- Hyun-Seok Whang
- Department of Physics and Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sug-Bong Choe
- Department of Physics and Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea.
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6
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Houshang A, Khymyn R, Fulara H, Gangwar A, Haidar M, Etesami SR, Ferreira R, Freitas PP, Dvornik M, Dumas RK, Åkerman J. Spin transfer torque driven higher-order propagating spin waves in nano-contact magnetic tunnel junctions. Nat Commun 2018; 9:4374. [PMID: 30348986 PMCID: PMC6197248 DOI: 10.1038/s41467-018-06589-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 09/12/2018] [Indexed: 11/08/2022] Open
Abstract
Short wavelength exchange-dominated propagating spin waves will enable magnonic devices to operate at higher frequencies and higher data transmission rates. While giant magnetoresistance (GMR)-based magnetic nanocontacts are efficient injectors of propagating spin waves, the generated wavelengths are 2.6 times the nano-contact diameter, and the electrical signal strength remains too weak for applications. Here we demonstrate nano-contact-based spin wave generation in magnetic tunnel junctions and observe large-frequency steps consistent with the hitherto ignored possibility of second- and third-order propagating spin waves with wavelengths of 120 and 74 nm, i.e., much smaller than the 150-nm nanocontact. Mutual synchronization is also observed on all three propagating modes. These higher-order propagating spin waves will enable magnonic devices to operate at much higher frequencies and greatly increase their transmission rates and spin wave propagating lengths, both proportional to the much higher group velocity.
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Affiliation(s)
- A Houshang
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
- NanOsc AB, 164 40, Kista, Sweden
| | - R Khymyn
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - H Fulara
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - A Gangwar
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - M Haidar
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - S R Etesami
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - R Ferreira
- International Iberian Nanotechnology Laboratory, Braga, 4715-330, Portugal
| | - P P Freitas
- International Iberian Nanotechnology Laboratory, Braga, 4715-330, Portugal
| | - M Dvornik
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - R K Dumas
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden
| | - J Åkerman
- Physics Department, University of Gothenburg, 412 96, Gothenburg, Sweden.
- NanOsc AB, 164 40, Kista, Sweden.
- Material Physics, School of Engineering Sciences, Royal Institute of Technology, Electrum 229, 164 40, Kista, Sweden.
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7
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Tsunegi S, Taniguchi T, Lebrun R, Yakushiji K, Cros V, Grollier J, Fukushima A, Yuasa S, Kubota H. Scaling up electrically synchronized spin torque oscillator networks. Sci Rep 2018; 8:13475. [PMID: 30194358 PMCID: PMC6128876 DOI: 10.1038/s41598-018-31769-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 08/21/2018] [Indexed: 11/29/2022] Open
Abstract
Synchronized nonlinear oscillators networks are at the core of numerous families of applications including phased array wave generators and neuromorphic pattern matching systems. In these devices, stable synchronization between large numbers of nanoscale oscillators is a key issue that remains to be demonstrated. Here, we show experimentally that synchronized spin-torque oscillator networks can be scaled up. By increasing the number of synchronized oscillators up to eight, we obtain that the emitted power and the quality factor increase linearly with the number of oscillators. Even more importantly, we demonstrate that the stability of synchronization in time exceeds 1.6 milliseconds corresponding to 105 periods of oscillation. Our study demonstrates that spin-torque oscillators are suitable for applications based on synchronized networks of oscillators.
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Affiliation(s)
- Sumito Tsunegi
- Spintronics Research Center, National Institute of Advanced Industrial Science And Technology (AIST), Tsukuba, 305-8568, Japan.
| | - Tomohiro Taniguchi
- Spintronics Research Center, National Institute of Advanced Industrial Science And Technology (AIST), Tsukuba, 305-8568, Japan
| | - Romain Lebrun
- Unité Mixte de Physique CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, 91767, Palaiseau, France
- Institute for Physics, Johannes Gutenberg-University Mainz, 55099, Mainz, Germany
| | - Kay Yakushiji
- Spintronics Research Center, National Institute of Advanced Industrial Science And Technology (AIST), Tsukuba, 305-8568, Japan
| | - Vincent Cros
- Unité Mixte de Physique CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, 91767, Palaiseau, France.
| | - Julie Grollier
- Unité Mixte de Physique CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - Akio Fukushima
- Spintronics Research Center, National Institute of Advanced Industrial Science And Technology (AIST), Tsukuba, 305-8568, Japan
| | - Shinji Yuasa
- Spintronics Research Center, National Institute of Advanced Industrial Science And Technology (AIST), Tsukuba, 305-8568, Japan
| | - Hitoshi Kubota
- Spintronics Research Center, National Institute of Advanced Industrial Science And Technology (AIST), Tsukuba, 305-8568, Japan
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8
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Tortarolo M, Lacoste B, Hem J, Dieudonné C, Cyrille MC, Katine JA, Mauri D, Zeltser A, Buda-Prejbeanu LD, Ebels U. Injection locking at 2f of spin torque oscillators under influence of thermal noise. Sci Rep 2018; 8:1728. [PMID: 29379128 PMCID: PMC5789033 DOI: 10.1038/s41598-017-18969-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/18/2017] [Indexed: 11/16/2022] Open
Abstract
Integration of Spin Torque Nano-Oscillators STNO’s in conventional microwave circuits means that the devices have to meet certain specifications. One of the most important criteria is the phase noise, being the key parameter to evaluate the performance and define possible applications. Phase locking several oscillators together has been suggested as a possible means to decrease phase noise and consequently, the linewidth. In this work we present experiments, numerical simulations and an analytic model to describe the effects of thermal noise in the injection locking of a tunnel junction based STNO. The analytics show the relation of the intrinsic parameters of the STNO with the phase noise level, opening the path to tailor the spectral characteristics by the magnetic configuration. Experiments and simulations demonstrate that in the in-plane magnetized structure, while the frequency is locked, much higher reference currents are needed to reduce the noise by phase locking. Moreover, our analysis shows that it is possible to control the phase noise by the reference microwave current (IRF) and that it can be further reduced by increasing the bias current (IDC) of the oscillator, keeping the reference current in feasible limits for applications.
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Affiliation(s)
- M Tortarolo
- Centro Atómico Constituyentes CNEA, 1650 San Martín and Consejo Nacional de Investigaciones Científicas y Técnicas, C1033AAJ, Buenos Aires, Argentina.
| | - B Lacoste
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC, SPINTEC, F38000, Grenoble, France.,International Iberian Nanotechnology Laboratory, Braga, Portugal
| | - J Hem
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC, SPINTEC, F38000, Grenoble, France
| | - C Dieudonné
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC, SPINTEC, F38000, Grenoble, France
| | - M-C Cyrille
- Univ. Grenoble Alpes, CEA-LETI MINATEC-CAMPUS, 38000, Grenoble, France
| | - J A Katine
- HGST, 3403 Yerba Buena Road, San Jose, California, 95135, USA
| | - D Mauri
- HGST, 3403 Yerba Buena Road, San Jose, California, 95135, USA
| | - A Zeltser
- HGST, 3403 Yerba Buena Road, San Jose, California, 95135, USA
| | - L D Buda-Prejbeanu
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC, SPINTEC, F38000, Grenoble, France
| | - U Ebels
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC, SPINTEC, F38000, Grenoble, France
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9
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Torunbalci MM, Gosavi TA, Camsari KY, Bhave SA. Magneto Acoustic Spin Hall Oscillators. Sci Rep 2018; 8:1119. [PMID: 29348416 PMCID: PMC5773673 DOI: 10.1038/s41598-018-19443-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 01/02/2018] [Indexed: 11/14/2022] Open
Abstract
This paper introduces a novel oscillator that combines the tunability of spin Hall-driven nano oscillators with the high quality factor (Q) of high overtone bulk acoustic wave resonators (HBAR), integrating both reference and tunable oscillators on the same chip with CMOS. In such magneto acoustic spin Hall (MASH) oscillators, voltage oscillations across the magnetic tunnel junction (MTJ) that arise from a spin-orbit torque (SOT) are shaped by the transmission response of the HBAR that acts as a multiple peak-bandpass filter and a delay element due to its large time constant, providing delayed feedback. The filtered voltage oscillations can be fed back to the MTJ via (a) strain, (b) current, or (c) magnetic field. We develop a SPICE-based circuit model by combining experimentally benchmarked models including the stochastic Landau-Lifshitz-Gilbert (sLLG) equation for magnetization dynamics and the Butterworth Van Dyke (BVD) circuit for the HBAR. Using the self-consistent model, we project up to ~50X enhancement in the oscillator linewidth with Q reaching up to 52825 at 3 GHz, while preserving the tunability by locking the STNO to the nearest high Q peak of the HBAR. We expect that our results will inspire MEMS-based solutions to spintronic devices by combining attractive features of both fields for a variety of applications.
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Affiliation(s)
- Mustafa Mert Torunbalci
- Purdue University, School of Electrical and Computer Engineering, West Lafayette, IN, 47907, USA.
| | - Tanay Arun Gosavi
- Cornell University, School of Electrical and Computer Engineering, Ithaca, NY, 14853, USA
| | - Kerem Yunus Camsari
- Purdue University, School of Electrical and Computer Engineering, West Lafayette, IN, 47907, USA
| | - Sunil Ashok Bhave
- Purdue University, School of Electrical and Computer Engineering, West Lafayette, IN, 47907, USA
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10
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Katkova O, Safin A, Udalov N, Kapranov M. Phase Dynamics in Arrays of Coupled Vortex Spin-Torque Nano-Oscillators. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201818503010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work, the mode analysis technique of complex networks nonlinear selfoscillatory vortex-based spin-torque nano-oscillattors (STNOs) with nonidentity and nonisochrony is developed. We construct adjacency matrices of different type of networks and calculate the normal modes. After the calculation of normal modes we shift to truncated equations for slowly varying amplitudes and phases in the normal coordinates using generalized quasi-Hamiltonian approach. Finally, we present the phase dynamics based on the Kuramotoapproach and compare different networks to the ability of synchronization.
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11
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High power and low critical current density spin transfer torque nano-oscillators using MgO barriers with intermediate thickness. Sci Rep 2017; 7:7237. [PMID: 28775263 PMCID: PMC5543117 DOI: 10.1038/s41598-017-07762-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 07/03/2017] [Indexed: 12/03/2022] Open
Abstract
Reported steady-state microwave emission in magnetic tunnel junction (MTJ)-based spin transfer torque nano-oscillators (STNOs) relies mostly on very thin insulating barriers [resulting in a resistance × area product (R × A) of ~1 Ωμm2] that can sustain large current densities and thus trigger large orbit magnetic dynamics. Apart from the low R × A requirement, the role of the tunnel barrier in the dynamics has so far been largely overlooked, in comparison to the magnetic configuration of STNOs. In this report, STNOs with an in-plane magnetized homogeneous free layer configuration are used to probe the role of the tunnel barrier in the dynamics. In this type of STNOs, the RF modes are in the GHz region with integrated matched output powers (Pout) in the range of 1–40 nW. Here, Pout values up to 200 nW are reported using thicker insulating barriers for junctions with R × A values ranging from 7.5 to 12.5 Ωμm2, without compromising the ability to trigger self-sustained oscillations and without any noticeable degradation of the signal linewidth (Γ). Furthermore, a decrease of two orders of magnitude in the critical current density for spin transfer torque induced dynamics (JSTT) was observed, without any further change in the magnetic configuration.
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12
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Li Y, de Milly X, Abreu Araujo F, Klein O, Cros V, Grollier J, de Loubens G. Probing Phase Coupling Between Two Spin-Torque Nano-Oscillators with an External Source. PHYSICAL REVIEW LETTERS 2017; 118:247202. [PMID: 28665656 DOI: 10.1103/physrevlett.118.247202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Indexed: 06/07/2023]
Abstract
Phase coupling between auto-oscillators is central for achieving coherent responses such as synchronization. Here we present an experimental approach to probe it in the case of two dipolarly coupled spin-torque vortex nano-oscillators using an external microwave field. By phase locking one oscillator to the external source, we observe frequency pulling on the second oscillator. From coupled phase equations we show analytically that this frequency pulling results from concerted actions of oscillator-oscillator and source-oscillator couplings. The analysis allows us to determine the strength and phase shift of coupling between two oscillators, yielding important information for the implementation of large interacting oscillator networks.
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Affiliation(s)
- Yi Li
- Service de Physique de l'État Condensé, CEA, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Xavier de Milly
- Service de Physique de l'État Condensé, CEA, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Flavio Abreu Araujo
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Olivier Klein
- SPINTEC, Université Grenoble Alpes, CEA, CNRS, 38000 Grenoble, France
| | - Vincent Cros
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Julie Grollier
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - Grégoire de Loubens
- Service de Physique de l'État Condensé, CEA, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
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13
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Mutual synchronization of spin torque nano-oscillators through a long-range and tunable electrical coupling scheme. Nat Commun 2017; 8:15825. [PMID: 28604670 PMCID: PMC5472782 DOI: 10.1038/ncomms15825] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 05/01/2017] [Indexed: 11/24/2022] Open
Abstract
The concept of spin-torque-driven high-frequency magnetization dynamics, allows the potential construction of complex networks of non-linear dynamical nanoscale systems, combining the field of spintronics and the study of non-linear systems. In the few previous demonstrations of synchronization of several spin-torque oscillators, the short-range nature of the magnetic coupling that was used has largely hampered a complete control of the synchronization process. Here we demonstrate the successful mutual synchronization of two spin-torque oscillators with a large separation distance through their long range self-emitted microwave currents. This leads to a strong improvement of both the emitted power and the linewidth. The full control of the synchronized state is achieved at the nanoscale through two active spin transfer torques, but also externally through an electrical delay line. These additional levels of control of the synchronization capability provide a new approach to develop spin-torque oscillator-based nanoscale microwave-devices going from microwave-sources to bio-inspired networks. The spintronics based complex network is promising for next generation computing systems but hampered by short-range spin-wave coupling. The authors make progress by achieving long range and tunable mutual synchronization of two spin-torque oscillators with improved emission power and signal linewidth.
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Hellman F, Hoffmann A, Tserkovnyak Y, Beach GSD, Fullerton EE, Leighton C, MacDonald AH, Ralph DC, Arena DA, Dürr HA, Fischer P, Grollier J, Heremans JP, Jungwirth T, Kimel AV, Koopmans B, Krivorotov IN, May SJ, Petford-Long AK, Rondinelli JM, Samarth N, Schuller IK, Slavin AN, Stiles MD, Tchernyshyov O, Thiaville A, Zink BL. Interface-Induced Phenomena in Magnetism. REVIEWS OF MODERN PHYSICS 2017; 89:025006. [PMID: 28890576 PMCID: PMC5587142 DOI: 10.1103/revmodphys.89.025006] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
This article reviews static and dynamic interfacial effects in magnetism, focusing on interfacially-driven magnetic effects and phenomena associated with spin-orbit coupling and intrinsic symmetry breaking at interfaces. It provides a historical background and literature survey, but focuses on recent progress, identifying the most exciting new scientific results and pointing to promising future research directions. It starts with an introduction and overview of how basic magnetic properties are affected by interfaces, then turns to a discussion of charge and spin transport through and near interfaces and how these can be used to control the properties of the magnetic layer. Important concepts include spin accumulation, spin currents, spin transfer torque, and spin pumping. An overview is provided to the current state of knowledge and existing review literature on interfacial effects such as exchange bias, exchange spring magnets, spin Hall effect, oxide heterostructures, and topological insulators. The article highlights recent discoveries of interface-induced magnetism and non-collinear spin textures, non-linear dynamics including spin torque transfer and magnetization reversal induced by interfaces, and interfacial effects in ultrafast magnetization processes.
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Affiliation(s)
- Frances Hellman
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Axel Hoffmann
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Yaroslav Tserkovnyak
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Geoffrey S D Beach
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Eric E Fullerton
- Center for Memory and Recording Research, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0401, USA
| | - Chris Leighton
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Allan H MacDonald
- Department of Physics, University of Texas at Austin, Austin, Texas 78712-0264, USA
| | - Daniel C Ralph
- Physics Department, Cornell University, Ithaca, New York 14853, USA; Kavli Institute at Cornell, Cornell University, Ithaca, New York 14853, USA
| | - Dario A Arena
- Department of Physics, University of South Florida, Tampa, Florida 33620-7100, USA
| | - Hermann A Dürr
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - Peter Fischer
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; Physics Department, University of California, 1156 High Street, Santa Cruz, California 94056, USA
| | - Julie Grollier
- Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Avenue Fresnel, 91767 Palaiseau, France
| | - Joseph P Heremans
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210, USA; Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210, USA; Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Tomas Jungwirth
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53 Praha 6, Czech Republic; School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Alexey V Kimel
- Radboud University, Institute for Molecules and Materials, Nijmegen 6525 AJ, The Netherlands
| | - Bert Koopmans
- Department of Applied Physics, Center for NanoMaterials, COBRA Research Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Ilya N Krivorotov
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
| | - Steven J May
- Department of Materials Science & Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA
| | - Amanda K Petford-Long
- Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, USA
| | - James M Rondinelli
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Nitin Samarth
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Ivan K Schuller
- Department of Physics and Center for Advanced Nanoscience, University of California, San Diego, La Jolla, California 92093, USA; Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Andrei N Slavin
- Department of Physics, Oakland University, Rochester, Michigan 48309, USA
| | - Mark D Stiles
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6202, USA
| | - Oleg Tchernyshyov
- Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - André Thiaville
- Laboratoire de Physique des Solides, UMR CNRS 8502, Université Paris-Sud, 91405 Orsay, France
| | - Barry L Zink
- Department of Physics and Astronomy, University of Denver, Denver, CO 80208, USA
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15
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Banuazizi SAH, Sani SR, Eklund A, Naiini MM, Mohseni SM, Chung S, Dürrenfeld P, Malm BG, Åkerman J. Order of magnitude improvement of nano-contact spin torque nano-oscillator performance. NANOSCALE 2017; 9:1896-1900. [PMID: 28094381 DOI: 10.1039/c6nr07309c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Spin torque nano-oscillators (STNO) represent a unique class of nano-scale microwave signal generators and offer a combination of intriguing properties, such as nano sized footprint, ultrafast modulation rates, and highly tunable microwave frequencies from 100 MHz to close to 100 GHz. However, their low output power and relatively high threshold current still limit their applicability and must be improved. In this study, we investigate the influence of the bottom Cu electrode thickness (tCu) in nano-contact STNOs based on Co/Cu/NiFe GMR stacks and with nano-contact diameters ranging from 60 to 500 nm. Increasing tCu from 10 to 70 nm results in a 40% reduction of the threshold current, an order of magnitude higher microwave output power, and close to two orders of magnitude better power conversion efficiency. Numerical simulations of the current distribution suggest that these dramatic improvements originate from a strongly reduced lateral current spread in the magneto-dynamically active region.
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Affiliation(s)
- Seyed Amir Hossein Banuazizi
- Department of Materials and Nano Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden.
| | - Sohrab R Sani
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Anders Eklund
- Department of Integrated Devices and Circuits, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden
| | - Maziar M Naiini
- Department of Integrated Devices and Circuits, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden
| | | | - Sunjae Chung
- Department of Materials and Nano Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden. and Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
| | - Philipp Dürrenfeld
- Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
| | - B Gunnar Malm
- Department of Integrated Devices and Circuits, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden
| | - Johan Åkerman
- Department of Materials and Nano Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden. and Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden and NanOsc AB, Electrum 205, 164 40 Kista, Sweden
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16
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Houshang A, Iacocca E, Dürrenfeld P, Sani SR, Åkerman J, Dumas RK. Spin-wave-beam driven synchronization of nanocontact spin-torque oscillators. NATURE NANOTECHNOLOGY 2016; 11:280-286. [PMID: 26689379 DOI: 10.1038/nnano.2015.280] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 10/26/2015] [Indexed: 06/05/2023]
Abstract
The synchronization of multiple nanocontact spin-torque oscillators (NC-STOs) is mediated by propagating spin waves (SWs). Although it has been shown that the Oersted field generated in the vicinity of the NC can dramatically alter the emission pattern of SWs, its role in the synchronization behaviour of multiple NCs has not been considered so far. Here we investigate the synchronization behaviour in multiple NC-STOs oriented either vertically or horizontally, with respect to the in-plane component of the external field. Synchronization is promoted (impeded) by the Oersted field landscape when the NCs are oriented vertically (horizontally) due to the highly anisotropic SW propagation. Not only is robust synchronization between two oscillators observed for separations larger than 1,000 nm, but synchronization of up to five oscillators, a new record, has been observed in the vertical array geometry. Furthermore, the synchronization can no longer be considered mutual in nature.
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Affiliation(s)
- A Houshang
- Physics Department, University of Gothenburg, Gothenburg 412 96, Sweden
- NanOsc AB, Kista 164 40, Sweden
| | - E Iacocca
- Physics Department, University of Gothenburg, Gothenburg 412 96, Sweden
- NanOsc AB, Kista 164 40, Sweden
| | - P Dürrenfeld
- Physics Department, University of Gothenburg, Gothenburg 412 96, Sweden
| | - S R Sani
- Material Physics, School of ICT, Royal Institute of Technology, Electrum 229, Kista 164 40, Sweden
| | - J Åkerman
- Physics Department, University of Gothenburg, Gothenburg 412 96, Sweden
- NanOsc AB, Kista 164 40, Sweden
- Material Physics, School of ICT, Royal Institute of Technology, Electrum 229, Kista 164 40, Sweden
| | - R K Dumas
- Physics Department, University of Gothenburg, Gothenburg 412 96, Sweden
- NanOsc AB, Kista 164 40, Sweden
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17
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Efficient Synchronization of Dipolarly Coupled Vortex-Based Spin Transfer Nano-Oscillators. Sci Rep 2015. [PMID: 26608230 DOI: 10.1038/srep17039(2015)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Due to their nonlinear properties, spin transfer nano-oscillators can easily adapt their frequency to external stimuli. This makes them interesting model systems to study the effects of synchronization and brings some opportunities to improve their microwave characteristics in view of their applications in information and communication technologies and/or to design innovative computing architectures. So far, mutual synchronization of spin transfer nano-oscillators through propagating spinwaves and exchange coupling in a common magnetic layer has been demonstrated. Here we show that the dipolar interaction is also an efficient mechanism to synchronize neighbouring oscillators. We experimentally study a pair of vortex-based spin transfer nano-oscillators, in which mutual synchronization can be achieved despite a significant frequency mismatch between oscillators. Importantly, the coupling efficiency is controlled by the magnetic configuration of the vortices, as confirmed by an analytical model and micromagnetic simulations highlighting the physics at play in the synchronization process.
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18
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Locatelli N, Hamadeh A, Abreu Araujo F, Belanovsky AD, Skirdkov PN, Lebrun R, Naletov VV, Zvezdin KA, Muñoz M, Grollier J, Klein O, Cros V, de Loubens G. Efficient Synchronization of Dipolarly Coupled Vortex-Based Spin Transfer Nano-Oscillators. Sci Rep 2015; 5:17039. [PMID: 26608230 PMCID: PMC4660301 DOI: 10.1038/srep17039] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/08/2015] [Indexed: 11/09/2022] Open
Abstract
Due to their nonlinear properties, spin transfer nano-oscillators can easily adapt their frequency to external stimuli. This makes them interesting model systems to study the effects of synchronization and brings some opportunities to improve their microwave characteristics in view of their applications in information and communication technologies and/or to design innovative computing architectures. So far, mutual synchronization of spin transfer nano-oscillators through propagating spinwaves and exchange coupling in a common magnetic layer has been demonstrated. Here we show that the dipolar interaction is also an efficient mechanism to synchronize neighbouring oscillators. We experimentally study a pair of vortex-based spin transfer nano-oscillators, in which mutual synchronization can be achieved despite a significant frequency mismatch between oscillators. Importantly, the coupling efficiency is controlled by the magnetic configuration of the vortices, as confirmed by an analytical model and micromagnetic simulations highlighting the physics at play in the synchronization process.
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Affiliation(s)
- Nicolas Locatelli
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, F91767 Palaiseau, France
| | - Abbass Hamadeh
- Service de Physique de l'Etat Condensé, CEA, CNRS, Université Paris-Saclay, CEA Saclay, F91191 Gif-sur-Yvette, France
| | - Flavio Abreu Araujo
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, BE-1348 Louvain-la-Neuve, Belgium
| | - Anatoly D Belanovsky
- Moscow Institute of Physics and Technology (State University), Institutskiy per. 9, 141700 Dolgoprudny, Russia.,A. M. Prokhorov General Physics Institute, RAS, Vavilova 38, Moscow, Russia
| | - Petr N Skirdkov
- Moscow Institute of Physics and Technology (State University), Institutskiy per. 9, 141700 Dolgoprudny, Russia.,A. M. Prokhorov General Physics Institute, RAS, Vavilova 38, Moscow, Russia
| | - Romain Lebrun
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, F91767 Palaiseau, France
| | - Vladimir V Naletov
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, F91767 Palaiseau, France.,Service de Physique de l'Etat Condensé, CEA, CNRS, Université Paris-Saclay, CEA Saclay, F91191 Gif-sur-Yvette, France.,Institute of Physics, Kazan Federal University, Kazan 420008, Russian Federation
| | - Konstantin A Zvezdin
- Moscow Institute of Physics and Technology (State University), Institutskiy per. 9, 141700 Dolgoprudny, Russia.,A. M. Prokhorov General Physics Institute, RAS, Vavilova 38, Moscow, Russia.,Istituto P.M. srl, Via Grassi 4, Torino, Italy
| | - Manuel Muñoz
- Instituto de Microelectrónica de Madrid-IMM (CNM-CSIC), Isaac Newton 8-PTM, 28760 Tres Cantos, Madrid, Spain
| | - Julie Grollier
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, F91767 Palaiseau, France
| | - Olivier Klein
- Service de Physique de l'Etat Condensé, CEA, CNRS, Université Paris-Saclay, CEA Saclay, F91191 Gif-sur-Yvette, France
| | - Vincent Cros
- Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, F91767 Palaiseau, France
| | - Grégoire de Loubens
- Service de Physique de l'Etat Condensé, CEA, CNRS, Université Paris-Saclay, CEA Saclay, F91191 Gif-sur-Yvette, France
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19
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Abstract
A linear array of periodically spaced and individually controllable skyrmions is introduced as a magnonic crystal. It is numerically demonstrated that skyrmion nucleation and annihilation can be accurately controlled by a nanosecond spin polarized current pulse through a nanocontact. Arranged in a periodic array, such nanocontacts allow the creation of a skyrmion lattice that causes a periodic modulation of the waveguide's magnetization, which can be dynamically controlled by changing either the strength of an applied external magnetic field or the density of the injected spin current through the nanocontacts. The skyrmion diameter is highly dependent on both the applied field and the injected current. This implies tunability of the lowest band gap as the skyrmion diameter directly affects the strength of the pinning potential. The calculated magnonic spectra thus exhibit tunable allowed frequency bands and forbidden frequency bandgaps analogous to that of conventional magnonic crystals where, in contrast, the periodicity is structurally induced and static. In the dynamic magnetic crystal studied here, it is possible to dynamically turn on and off the artificial periodic structure, which allows switching between full rejection and full transmission of spin waves in the waveguide. These findings should stimulate further research activities on multiple functionalities offered by magnonic crystals based on periodic skyrmion lattices.
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Affiliation(s)
- Fusheng Ma
- †Temasek Laboratories, National University of Singapore, 119077 Singapore
| | - Yan Zhou
- ‡Department of Physics, University of Hong Kong, Hong Kong, P. R. China
- ⊥York-Nanjing Joint Center for Spintronics and Nano Engineering (YNJC), School of Electronics Science and Engineering, Nanjing University, Nanjing 210093, China
| | - H B Braun
- §School of Physics, University College Dublin, Dublin 4, Ireland
| | - W S Lew
- ∥School of Physical and Mathematical Sciences, Nanyang Technological University, 639798 Singapore
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