Magnon polarons in the spin Peltier effect

TL;DR

This paper reports the observation of magnon polarons affecting the spin Peltier effect in a specific magnetic material, revealing how hybridized magnon-phonon excitations enhance spin current lifetime and influence thermal spin transport.

Contribution

It demonstrates the direct observation of magnon polarons in the spin Peltier effect and links hybridized magnon-phonon excitations to increased spin current lifetime.

Findings

SPE peaks align with magnon-polaron formation thresholds

Magnon-phonon hybridization enhances spin current lifetime

Observation consistent with previous spin Seebeck effect studies

Abstract

We report the observation of anomalous peak structures induced by hybridized magnon-phonon excitation (magnon polarons) in the magnetic field dependence of the spin Peltier effect (SPE) in a Lu$_{2}$Bi$_{1}$Fe$_{4}$Ga$_{1}$O$_{12}$ (BiGa:LuIG) with Pt contact. The SPE peaks coincide with magnetic fields tuned to the threshold of magnon-polaron formation, consistent with the previous observation in the spin Seebeck effect. The enhancement of SPE is attributed to the lifetime increase in spin current caused by magnon-phonon hybridization in BiGa:LuIG.