Effects of delayed feedback on the power spectrum of spin-torque nano-oscillators

Williame, Jérôme; Kim, Joo-Von

doi:10.1088/1361-6463/abaf26

Cited by 5 publications

(1 citation statement)

References 58 publications

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“…Let us briefly mention applicability of the chaotic dynamics for practical devices. Chaos in spintronics devices has been studied both experimentally and theoretically using various methods [48][49][50][51][52][53][54][55][56][57] . An excitation of chaos in spintronics devices may evoke interest from a viewpoint of brain-inspired computing 58,59 .…”

Section: /14mentioning

confidence: 99%

Non-periodic input-driven magnetization dynamics in voltage-controlled parametric oscillator

Taniguchi

2022

Journal of Magnetism and Magnetic Materials

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Section: /14mentioning

confidence: 99%

Non-periodic input-driven magnetization dynamics in voltage-controlled parametric oscillator

Taniguchi

2022

Journal of Magnetism and Magnetic Materials

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Bifurcation to complex dynamics in largely modulated voltage-controlled parametric oscillator

Taniguchi

2024

Sci Rep

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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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A magnetic domain wall Mackey–Glass oscillator

Williame

Kim

2021

Applied Physics Letters

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We propose a time-delay oscillator using Mackey–Glass nonlinearity based on a pinned magnetic domain wall in a thin film nanostrip. Through spin transfer torques, electric currents applied along the strip cause the domain wall to deform and displace away from a geometrical pinning site, which can be converted into a nonlinear transfer function through a suitable choice of a readout. This readout serves as a delay signal, which is subsequently fed back into the applied current with amplification. With micromagnetics simulations, we study the role of the readout position, time delay, and feedback gain on the dynamics of this domain wall. In particular, we highlight regimes in which self-sustained oscillations and complex transients are possible.

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Effects of delayed feedback on the power spectrum of spin-torque nano-oscillators

Cited by 5 publications

References 58 publications

Non-periodic input-driven magnetization dynamics in voltage-controlled parametric oscillator

Non-periodic input-driven magnetization dynamics in voltage-controlled parametric oscillator

Bifurcation to complex dynamics in largely modulated voltage-controlled parametric oscillator

A magnetic domain wall Mackey–Glass oscillator

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