Magnetoelastic Gilbert damping in magnetostrictive Fe$_{0.7}$Ga$_{0.3}$ thin films

TL;DR

This study reveals a significant anisotropic enhancement of Gilbert damping in Fe$_{0.7}$Ga$_{0.3}$ thin films due to magnetoelastic effects, influenced by temperature and magnetic field orientation, with broadband FMR measurements supporting these findings.

Contribution

It demonstrates the large anisotropy of magnetoelastic Gilbert damping in Fe$_{0.7}$Ga$_{0.3}$ films and elucidates the roles of magnetostriction and phonon relaxation through temperature-dependent measurements.

Findings

Enhanced magnetoelastic damping in Fe$_{0.7}$Ga$_{0.3}$ films

Damping anisotropy up to a factor of 10 at room temperature

Temperature and field orientation influence damping behavior

Abstract

We report an enhanced magnetoelastic contribution to the Gilbert damping in highly magnetostrictive Fe$_{0.7}$Ga$_{0.3}$ thin films. This effect is mitigated for perpendicular-to-plane fields, leading to a large anisotropy of the Gilbert damping in all of the films (up to a factor of 10 at room temperature). These claims are supported by broadband measurements of the ferromagnetic resonance linewidths over a range of temperatures (5 to 400 K), which serve to elucidate the effect of both the magnetostriction and phonon relaxation on the magnetoelastic Gilbert damping.