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Updated: Jun 27, 2025

Fabrication and Characterization of Superconducting Resonators
Published on: May 21, 2016
Magnon-Phonon Coupling of Synthetic Antiferromagnets in a Surface Acoustic Wave Cavity Resonator
Hiroki Matsumoto1, Isamu Yasuda1, Motoki Asano2
1Department of Physics, The University of Tokyo, Hongo, Tokyo 113-0033, Japan.
Abstract:
We used a surface acoustic wave (SAW) cavity resonator to study the coupling of acoustic magnons in a synthetic antiferromagnet (SAF) and phonons carried by SAWs. The SAF is composed of a CoFeB/Ru/CoFeB trilayer, and the scattering matrix of the SAW resonator is studied to assess the coupling. We find that the spectral line width of the SAW resonator is modulated when the frequency of the excited magnons approaches the SAW resonance frequency. Such a change in the spectral linewidth can be well reproduced using macrospin-like model calculations. From the model analyses, we estimate the magnon-phonon coupling strength to be ∼9.9 MHz at a SAW resonance frequency of 1.8 GHz: the corresponding magnomechanical cooperativity is ∼0.66. As the spectral shape hardly changes in a CoFeB single-layer reference sample, these results show that SAF provides an ideal platform to study magnon-phonon coupling in an SAW cavity resonator.
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