Phonon-modulated magnon transport via ferromagnetic resonance in a nonlocal YIG/Pt device

Abstract

Owing to magnetostrictive effects, nonlocal magnon transport in yttrium iron garnet (YIG) is often accompanied by phonon excitation. However, the influence of these phonons on magnon spin transport remains unclear. In our experiment, an external microwave field is applied to excite ferromagnetic resonance (FMR) in the YIG during nonlocal magnon transport measurements. We observe that an additional signal emerges in the thermal magnon transport. Angular-dependent measurements under varying magnetic fields further reveal that this additional signal is well described by our Landau–Lifshitz–Gilbert (LLG) simulation when enhanced magnetoelastic coupling is considered. This result indicates that the signal originates from the rotational lattice motion driven by magnetization precession, which generates phonons that subsequently couple to propagating magnons. This behavior contrasts with previously reported magnon–magnon scattering and parametric pumping, which occur strictly under resonant FMR conditions and require nonlinear excitation. Our results provide evidence that phonons actively participate in magnon spin transport and suggest viable opportunities for developing high-speed, phonon-assisted magnonic devices.