Magnon Polarons in the Spin Seebeck Effect

TL;DR

This paper investigates how magnon-phonon interactions influence the spin Seebeck effect in YIG, revealing sharp features linked to magnon-polaron formation and providing insights into lattice and magnetization dynamics.

Contribution

It demonstrates that the magnetoelastic coupling explains the observed SSE anomalies and offers a quantitative model matching experimental data.

Findings

Sharp SSE voltage structures are due to magnon-polaron formation.

Boltzmann theory with magnetoelastic coupling reproduces experimental results.

SSE anomalies reveal details about lattice and magnetization dynamics.

Abstract

Sharp structures in magnetic field-dependent spin Seebeck effect (SSE) voltages of Pt/Y$_{3}$Fe$_{5}$O$_{12}$ (YIG) at low temperatures are attributed to the magnon-phonon interaction. Experimental results are well reproduced by a Boltzmann theory that includes the magnetoelastic coupling (MEC). The SSE anomalies coincide with magnetic fields tuned to the threshold of magnon-polaron formation. The effect gives insight into the relative quality of the lattice and magnetization dynamics.