Large enhancement of spin-orbit torques under a MHz modulation due to phonon-magnon coupling

Fuente: arXiv
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Main Authors: Zhang, Hanying, Zhao, Qianwen, Jiang, Baiqing, Wang, Yuan, Xie, Tunan, Lou, Kaihua, Xia, ChaoChao, Bi, C.
Format: Preprint
Published: 2023
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author Zhang, Hanying
Zhao, Qianwen
Jiang, Baiqing
Wang, Yuan
Xie, Tunan
Lou, Kaihua
Xia, ChaoChao
Bi, C.
author_facet Zhang, Hanying
Zhao, Qianwen
Jiang, Baiqing
Wang, Yuan
Xie, Tunan
Lou, Kaihua
Xia, ChaoChao
Bi, C.
contents The discovery of spin-orbit torques (SOTs) generated through the spin Hall or Rashba effects provides an alternative write approach for magnetic random-access memory (MRAM), igniting the development of spin-orbitronics in recent years. Quantitative characterization of SOTs highly relies on the SOT-driven ferromagnetic resonance (ST-FMR), where a modulated microwave current is used to generate ac SOTs and the modulation-frequency is usually less than 100 kHz (the limit of conventional lock-in amplifiers). Here we have investigated the SOT of typical SOT material/ferromagnet bilayers in an extended modulation-frequency range, up to MHz, by developing the ST-FMR measurement. Remarkably, we found that the measured SOTs are enhanced about three times in the MHz range, which cannot be explained according to present SOT theory. We attribute the enhancement of SOT to additional magnon excitations due to phonon-magnon coupling, which is also reflected in the slight changes of resonant field and linewidth in the acquired ST-FMR spectra, corresponding to the modifications of effective magnetization and damping constant, respectively. Our results indicate that the write current of SOT-MRAM may be reduced with the assistant of phonon-magnon coupling.
format Preprint
id arxiv_https___arxiv_org_abs_2401_02967
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Large enhancement of spin-orbit torques under a MHz modulation due to phonon-magnon coupling
Zhang, Hanying
Zhao, Qianwen
Jiang, Baiqing
Wang, Yuan
Xie, Tunan
Lou, Kaihua
Xia, ChaoChao
Bi, C.
Mesoscale and Nanoscale Physics
Applied Physics
The discovery of spin-orbit torques (SOTs) generated through the spin Hall or Rashba effects provides an alternative write approach for magnetic random-access memory (MRAM), igniting the development of spin-orbitronics in recent years. Quantitative characterization of SOTs highly relies on the SOT-driven ferromagnetic resonance (ST-FMR), where a modulated microwave current is used to generate ac SOTs and the modulation-frequency is usually less than 100 kHz (the limit of conventional lock-in amplifiers). Here we have investigated the SOT of typical SOT material/ferromagnet bilayers in an extended modulation-frequency range, up to MHz, by developing the ST-FMR measurement. Remarkably, we found that the measured SOTs are enhanced about three times in the MHz range, which cannot be explained according to present SOT theory. We attribute the enhancement of SOT to additional magnon excitations due to phonon-magnon coupling, which is also reflected in the slight changes of resonant field and linewidth in the acquired ST-FMR spectra, corresponding to the modifications of effective magnetization and damping constant, respectively. Our results indicate that the write current of SOT-MRAM may be reduced with the assistant of phonon-magnon coupling.
title Large enhancement of spin-orbit torques under a MHz modulation due to phonon-magnon coupling
topic Mesoscale and Nanoscale Physics
Applied Physics
url https://arxiv.org/abs/2401.02967