Dzyaloshinskii-Moriya interaction induced extrinsic linewidth broadening of ferromagnetic resonance

TL;DR

This paper derives a quantum mechanical expression for extrinsic FMR linewidth in thin ferromagnetic films with Dzyaloshinskii-Moriya interaction, revealing characteristic features like finite linewidth at zero frequency and low-frequency peaks.

Contribution

It introduces a novel quantum mechanical model for extrinsic FMR linewidth considering DMI and structural inhomogeneity effects.

Findings

FMR linewidth exhibits finite value at zero frequency.

Presence of peaks in low-frequency range of linewidth.

Rich resonant states in magnon dispersion due to DMI.

Abstract

For a thin ferromagnetic film with the Dzyaloshinskii-Moriya interaction (DMI), we derive an expression of the extrinsic ferromagnetic resonance (FMR) linewidth in a quantum mechanical way, taking into account scatterings from structural inhomogeneity. In the presence of the DMI, the magnon dispersion exhibits rich resonant states, especially in small external magnetic fields and strong DMI strength. It is found that the FMR linewidth shows several characteristic features such as a finite linewidth at zero frequency and peaks in the low frequency range.