Journal ArticleDOI
Frequency transition of spin-torque oscillator under the magnetic-field pulse in nanosecond range
TLDR
In this article, a time domain study of the frequency transition of spin-torque oscillator (STO) under the magnetic-field pulse in nanosecond range is presented.Abstract:
We report a time domain study of the frequency transition of spin-torque oscillator (STO) under the magnetic-field pulse in nanosecond range. We fabricated the pillar-structured STO devices consisting of MgO-based tunnel junctions with CoFeB free layers. Single-shot waveforms of the STO were obtained using a real-time oscilloscope (40 GS/sec). First, we measured current dependence of the waveform to investigate the time-domain stability of the oscillation. With the increase in the dc current applied to the STO, the oscillation state changed continuously in the following order: thermal fluctuation, intermittent unsteady oscillation, steady oscillation, and chaotic oscillation. Next, we measured the response of the STO to the magnetic-field pulse with a rise time of 0.5 ns, a duration time of 10 ns, and an amplitude of 60 Oe. In this measurement, the oscillation state was kept in the above-mentioned steady state with the frequency ∼3.5 GHz and the spectral linewidth ∼50 MHz. In the presence of the magnetic-...read more
Citations
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Journal ArticleDOI
Spin nano-oscillator-based wireless communication.
Hyunseok Choi,Sun Yool Kang,Seong Jun Cho,Inn Yeal Oh,Mincheol Shin,Hyuncheol Park,Chaun Jang,Byoung-Chul Min,Sangil Kim,Seung-Young Park,Chul Soon Park +10 more
TL;DR: By adopting direct binary amplitude shift keying modulation and non–coherent demodulation, this work demonstrates STNO–based wireless communication with 200–kbps data rate at a distance of 1 m between transmitter and receiver.
Book ChapterDOI
Spin-Torque Oscillators
Joo-Von Kim,Joo-Von Kim +1 more
TL;DR: In this paper, the theoretical aspects of magnetization oscillations driven by spin torques, such as spin waves and vortex gyration, are presented in detail and key experimental results are highlighted.
Journal ArticleDOI
Evaluation of memory capacity of spin torque oscillator for recurrent neural networks
Sumito Tsunegi,Tomohiro Taniguchi,Shinji Miwa,Kohei Nakajima,Kohei Nakajima,Kay Yakushiji,Akio Fukushima,Shinji Yuasa,Hitoshi Kubota +8 more
TL;DR: In this paper, the memory capacity of a vortex-type spin torque oscillator used in recurrent neural networks for the first time was evaluated, and the capacity of the whole system including the oscillator was evaluated.
Journal ArticleDOI
Frequency shift keying by current modulation in a MTJ-based STNO with high data rate
A. Ruiz-Calaforra,A. Purbawati,Thomas Brächer,J. Hem,Chandrasekhar Murapaka,E. Jimenez,D. Mauri,A. Zeltser,Jordan A. Katine,Marie-Claire Cyrille,Liliana D. Buda-Prejbeanu,Ursula Ebels +11 more
TL;DR: In this article, the ability of a magnetic-tunnel-junction based spin torque nano-oscillator to respond to a binary input sequence encoded in a square-shaped current pulse for its application as a frequency-shift-keying (FSK) based emitter was investigated.
Journal ArticleDOI
Simulations and Experiments Toward High-Data-Transfer-Rate Readers Composed of a Spin-Torque Oscillator
TL;DR: In this article, the signal-to-noise ratios (SNRs) of the output signals under the thermal magnetization fluctuations are calculated by using the recent nonlinear theories, where the spin-torque oscillators (STO) senses the media field as a modulation in the oscillation frequency, enabling high data-transfer rates beyond the limit of ferromagnetic relaxation.
References
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Journal ArticleDOI
Nanoscale magnetic field detection using a spin torque oscillator
Patrick M. Braganca,Bruce A. Gurney,Bruce Alexander Wilson,Jordan A. Katine,S. Maat,Jeffrey R. Childress +5 more
TL;DR: This sensor's performance relies predominantly on STO properties such as spectral linewidth and frequency dispersion with magnetic field, rather than signal amplitude as in conventional magnetoresistive sensors, and is shown in measured devices to achieve large signal to noise ratios.
Journal ArticleDOI
Microwave power generated by a spin-torque oscillator in the presence of noise
TL;DR: In this article, an expression for the microwave power generated by a spin-torque oscillator in the presence of thermal noise is derived, when used in a subcritical regime.
Journal ArticleDOI
Microwave power generated by a spin-torque oscillator in the presence of noise
TL;DR: In this paper, an expression for the microwave power generated by a spin-torque oscillator in the presence of thermal noise is derived, when used in a subcritical regime.
Journal ArticleDOI
Numerical Simulation on Temporal Response of Spin-Torque Oscillator to Magnetic Pulses
TL;DR: In this paper, the phase response to a short magnetic pulse is numerically exemplified and the phase basically follows the magnetic pulse although it takes several nanoseconds to return to the steady state because of frequency nonlinearity.
Journal ArticleDOI
Signal-to-noise ratios in high-signal-transfer-rate read heads composed of spin-torque oscillators
TL;DR: In this article, an application of spin-torque oscillators (STO) to high-signal-transfer-rate read heads beyond 3 Gbits/s is considered and the signal-to-noise ratios (SNRs) of the output signals under the thermal magnetization fluctuations are calculated by using the results of recent nonlinear theories.