講演情報
[9p-N102-5]Hybridization of Spin Waves and Surface Acoustic Waves
〇Jorge Puebla1,2 (1.Kyoto Univ., 2.RIKEN Inst.)
キーワード：
Spintronics、Magnetoelasticity、Surface acoustic waves
The interaction between surface acoustic waves (SAWs) and spin waves is attracting growing interest in spintronics and magnetism [1]. While spin waves in ferromagnets are typically excited by microwave photons, they can also be driven by phonons, as predicted by Kittel [2]. When SAWs and spin waves strongly couple, hybrid quasiparticles emerge, blending phononic and magnonic characteristics. Our recent experiments demonstrate such hybridization at room temperature in an on-chip SAW device [3]. Using acoustic reflectors to form a low-loss cavity [4, 5] and CoFeB layers with low damping, we observed avoided crossing in the dispersion curves, a hallmark of strong coupling. SAW transmission data revealed bending in the phonon dispersion near magnon resonance. With a 10 nm CoFeB layer, energy absorption at ~30 mT was evident, but the dispersion remained linear. At 20 nm, both absorption and bending occurred, confirming strong coupling. This indicates that phonons acquire magnon-like properties and respond to magnetic fields, and vice versa, opening paths for hybrid-wave-based information and communication devices.
Furthermore, in the thin-film regime where the acoustic wavelength exceeds the magnetic layer thickness, we observed a monotonic increase in coupling strength with CoFeB thickness, suggesting a pathway toward ultra-strong coupling.
In this talk, I will present these findings and discuss their potential impact on future hybrid magnon-phonon devices, especially as improved experimental techniques enable deeper insight into their spatial, temporal, and phase dynamics.
Furthermore, in the thin-film regime where the acoustic wavelength exceeds the magnetic layer thickness, we observed a monotonic increase in coupling strength with CoFeB thickness, suggesting a pathway toward ultra-strong coupling.
In this talk, I will present these findings and discuss their potential impact on future hybrid magnon-phonon devices, especially as improved experimental techniques enable deeper insight into their spatial, temporal, and phase dynamics.