Phonon-induced magnetization dynamics in Co-doped iron garnets

TL;DR

This study explores how resonant optical phonon excitation can induce and control magnetization dynamics in Co-doped iron garnets, revealing phase-dependent precession and switching mechanisms.

Contribution

It provides the first combined experimental and numerical analysis of phonon-driven magnetization dynamics in iron garnets, highlighting the role of magneto-elastic energy changes.

Findings

Resonant optical phonon excitation induces spatially-varying magnetization precession.

Magnetization phase depends on external magnetic field direction.

Micromagnetic simulations match experimental precession and switching behavior.

Abstract

The developing field of strain-induced magnetization dynamics offers a promising path toward efficiently controlling spins and phase transitions. Understanding the underlying mechanisms is crucial in finding the optimal parameters supporting the phononic switching of magnetization. Here, we present an experimental and numerical study of time-resolved magnetization dynamics driven by the resonant excitation of an optical phonon mode in iron garnets. Upon pumping the latter with an infrared pulse obtained from a free-electron laser, we observe spatially-varying magnetization precession, with its phase depending on the direction of an external magnetic field. Our micromagnetic simulations effectively describe the magnetization precession and switching in terms of laser-induced changes in the crystal's magneto-elastic energy.