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Ang JM, Dananjaya PA, Chow SCW, Lim GJ, Seet CS, Lew WS. Enhancement of temperature-modulated NbO 2-based relaxation oscillator via interfacial and bulk treatments. NANOTECHNOLOGY 2023; 34:185202. [PMID: 36720156 DOI: 10.1088/1361-6528/acb778] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
This work demonstrates oscillation frequency modulation in a NbO2-based relaxation oscillator device, in which the oscillation frequency increases with operating temperature and source voltage, and decreases with load resistance. An annealing-induced oxygen diffusion at 373 K was carried out to optimize the stoichiometry of the bulk NbO2to achieve consistent oscillation frequency shift with device temperature. The device exhibits stable self-sustained oscillation in which the frequency can be modulated between 2 and 33 MHz, and a wider operating voltage range can be obtained. An additional surface treatment step was employed during fabrication to reduce the surface roughness of the bottom electrode and to remove surface contaminants that affect the interfacial properties of the device. The device frequency tunability coupled with high oscillating frequency and high endurance capability of more than 1.5 × 108cycles indicates that the Pt/NbO2/Pt device is particularly suitable for applications in an oscillatory neural network.
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Affiliation(s)
- Jia Min Ang
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
- GLOBALFOUNDRIES Singapore Pte. Ltd, 60 Woodlands Industrial Park D St 2, 738406, Singapore
| | - Putu Andhita Dananjaya
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Samuel Chen Wai Chow
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
- GLOBALFOUNDRIES Singapore Pte. Ltd, 60 Woodlands Industrial Park D St 2, 738406, Singapore
| | - Gerard Joseph Lim
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
| | - Chim Seng Seet
- GLOBALFOUNDRIES Singapore Pte. Ltd, 60 Woodlands Industrial Park D St 2, 738406, Singapore
| | - Wen Siang Lew
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore
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Zahedinejad M, Fulara H, Khymyn R, Houshang A, Dvornik M, Fukami S, Kanai S, Ohno H, Åkerman J. Memristive control of mutual spin Hall nano-oscillator synchronization for neuromorphic computing. NATURE MATERIALS 2022; 21:81-87. [PMID: 34845363 DOI: 10.1038/s41563-021-01153-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
Synchronization of large spin Hall nano-oscillator (SHNO) arrays is an appealing approach toward ultrafast non-conventional computing. However, interfacing to the array, tuning its individual oscillators and providing built-in memory units remain substantial challenges. Here, we address these challenges using memristive gating of W/CoFeB/MgO/AlOx-based SHNOs. In its high resistance state, the memristor modulates the perpendicular magnetic anisotropy at the CoFeB/MgO interface by the applied electric field. In its low resistance state the memristor adds or subtracts current to the SHNO drive. Both electric field and current control affect the SHNO auto-oscillation mode and frequency, allowing us to reversibly turn on/off mutual synchronization in chains of four SHNOs. We also demonstrate that two individually controlled memristors can be used to tune a four-SHNO chain into differently synchronized states. Memristor gating is therefore an efficient approach to input, tune and store the state of SHNO arrays for non-conventional computing models.
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Affiliation(s)
- Mohammad Zahedinejad
- Physics Department, University of Gothenburg, Gothenburg, Sweden
- NanOsc AB, Kista, Sweden
| | - Himanshu Fulara
- Physics Department, University of Gothenburg, Gothenburg, Sweden
- Department of Physics, Indian Institute of Technology Roorkee, Roorkee, India
| | - Roman Khymyn
- Physics Department, University of Gothenburg, Gothenburg, Sweden
| | - Afshin Houshang
- Physics Department, University of Gothenburg, Gothenburg, Sweden
| | | | - Shunsuke Fukami
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, Sendai, Japan
- Center for Spintronics Research Network, Tohoku University, Sendai, Japan
- Center for Innovative Integrated Electronic Systems, Tohoku University, Sendai, Japan
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
| | - Shun Kanai
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, Sendai, Japan
- Center for Spintronics Research Network, Tohoku University, Sendai, Japan
- Division for the Establishment of Frontier Sciences, Tohoku University, Sendai, Japan
| | - Hideo Ohno
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, Sendai, Japan
- Center for Spintronics Research Network, Tohoku University, Sendai, Japan
- Center for Innovative Integrated Electronic Systems, Tohoku University, Sendai, Japan
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai, Japan
| | - Johan Åkerman
- Physics Department, University of Gothenburg, Gothenburg, Sweden.
- NanOsc AB, Kista, Sweden.
- Material and Nanophysics, School of Engineering Sciences, KTH Royal Institute of Technology, Kista, Sweden.
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Mallphanov IL, Vanag VK. Chemical micro-oscillators based on the Belousov–Zhabotinsky reaction. RUSSIAN CHEMICAL REVIEWS 2021. [DOI: 10.1070/rcr5009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Abstract
The results of studies on the development of micro-oscillators (MOs) based on the Belousov –Zhabotinsky (BZ) oscillatory chemical reaction are integrated and systematized. The mechanisms of the BZ reaction and the methods of immobilization of the catalyst of the BZ reaction in micro-volumes are briefly discussed. Methods for creating BZ MOs based on water microdroplets in the oil phase and organic and inorganic polymer microspheres are considered. Methods of control and management of the dynamics of BZ MO networks are described, including methods of MO synchronization. The prospects for the design of neural networks of MOs with intelligent-like behaviour are outlined. Such networks present a new area of nonlinear chemistry, including, in particular, the creation of a chemical ‘computer’.
The bibliography includes 250 references.
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Corti E, Cornejo Jimenez JA, Niang KM, Robertson J, Moselund KE, Gotsmann B, Ionescu AM, Karg S. Coupled VO 2 Oscillators Circuit as Analog First Layer Filter in Convolutional Neural Networks. Front Neurosci 2021; 15:628254. [PMID: 33642984 PMCID: PMC7905171 DOI: 10.3389/fnins.2021.628254] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/06/2021] [Indexed: 11/30/2022] Open
Abstract
In this work we present an in-memory computing platform based on coupled VO2 oscillators fabricated in a crossbar configuration on silicon. Compared to existing platforms, the crossbar configuration promises significant improvements in terms of area density and oscillation frequency. Further, the crossbar devices exhibit low variability and extended reliability, hence, enabling experiments on 4-coupled oscillator. We demonstrate the neuromorphic computing capabilities using the phase relation of the oscillators. As an application, we propose to replace digital filtering operation in a convolutional neural network with oscillating circuits. The concept is tested with a VGG13 architecture on the MNIST dataset, achieving performances of 95% in the recognition task.
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Affiliation(s)
| | | | - Kham M Niang
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - John Robertson
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | | | | | - Adrian M Ionescu
- Nanoelectronic Devices Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Gong CC, Toenjes R, Pikovsky A. Coupled Möbius maps as a tool to model Kuramoto phase synchronization. Phys Rev E 2020; 102:022206. [PMID: 32942495 DOI: 10.1103/physreve.102.022206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 07/13/2020] [Indexed: 11/07/2022]
Abstract
We propose Möbius maps as a tool to model synchronization phenomena in coupled phase oscillators. Not only does the map provide fast computation of phase synchronization, it also reflects the underlying group structure of the sinusoidally coupled continuous phase dynamics. We study map versions of various known continuous-time collective dynamics, such as the synchronization transition in the Kuramoto-Sakaguchi model of nonidentical oscillators, chimeras in two coupled populations of identical phase oscillators, and Kuramoto-Battogtokh chimeras on a ring, and demonstrate similarities and differences between the iterated map models and their known continuous-time counterparts.
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Affiliation(s)
- Chen Chris Gong
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Straße 32, 14476 Potsdam, Germany
| | - Ralf Toenjes
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Straße 32, 14476 Potsdam, Germany
| | - Arkady Pikovsky
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Straße 32, 14476 Potsdam, Germany.,Department of Control Theory, Nizhny Novgorod State University, Gagarin Avenue 23, 606950 Nizhny Novgorod, Russia
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Zahedinejad M, Awad AA, Muralidhar S, Khymyn R, Fulara H, Mazraati H, Dvornik M, Åkerman J. Two-dimensional mutually synchronized spin Hall nano-oscillator arrays for neuromorphic computing. NATURE NANOTECHNOLOGY 2020; 15:47-52. [PMID: 31873287 DOI: 10.1038/s41565-019-0593-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 11/08/2019] [Indexed: 06/10/2023]
Abstract
In spin Hall nano-oscillators (SHNOs), pure spin currents drive local regions of magnetic films and nanostructures into auto-oscillating precession. If such regions are placed in close proximity to each other they can interact and may mutually synchronize. Here, we demonstrate robust mutual synchronization of two-dimensional SHNO arrays ranging from 2 × 2 to 8 × 8 nano-constrictions, observed both electrically and using micro-Brillouin light scattering microscopy. On short time scales, where the auto-oscillation linewidth [Formula: see text] is governed by white noise, the signal quality factor, [Formula: see text], increases linearly with the number of mutually synchronized nano-constrictions (N), reaching 170,000 in the largest arrays. We also show that SHNO arrays exposed to two independently tuned microwave frequencies exhibit the same synchronization maps as can be used for neuromorphic vowel recognition. Our demonstrations may hence enable the use of SHNO arrays in two-dimensional oscillator networks for high-quality microwave signal generation and ultra-fast neuromorphic computing.
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Affiliation(s)
- Mohammad Zahedinejad
- Physics Department, University of Gothenburg, Gothenburg, Sweden
- NanOsc AB, Kista, Sweden
| | - Ahmad A Awad
- Physics Department, University of Gothenburg, Gothenburg, Sweden
- NanOsc AB, Kista, Sweden
| | | | - Roman Khymyn
- Physics Department, University of Gothenburg, Gothenburg, Sweden
- NanOsc AB, Kista, Sweden
| | - Himanshu Fulara
- Physics Department, University of Gothenburg, Gothenburg, Sweden
- NanOsc AB, Kista, Sweden
| | - Hamid Mazraati
- NanOsc AB, Kista, Sweden
- Material and Nanophysics, School of Engineering Sciences, KTH Royal Institute of Technology, Kista, Sweden
| | - Mykola Dvornik
- Physics Department, University of Gothenburg, Gothenburg, Sweden
- NanOsc AB, Kista, Sweden
| | - Johan Åkerman
- Physics Department, University of Gothenburg, Gothenburg, Sweden.
- NanOsc AB, Kista, Sweden.
- Material and Nanophysics, School of Engineering Sciences, KTH Royal Institute of Technology, Kista, Sweden.
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