Large angle magnetization dynamics measured by time-resolved ferromagnetic resonance

TL;DR

This study employs a time-resolved ferromagnetic resonance technique to explore large-angle magnetization dynamics in Permalloy films, revealing nonlinear responses at high excitation amplitudes and comparing results with conventional methods.

Contribution

It introduces a time-resolved FMR method for large-angle magnetization dynamics and compares its results with traditional techniques, highlighting nonlinear effects at high excitation amplitudes.

Findings

Agreement with conventional methods at small angles

Observation of nonlinear magnetization response at large angles

Potential link to Suhl instabilities

Abstract

A time-resolved ferromagnetic resonance technique was used to investigate the magnetization dynamics of a 10 nm thin Permalloy film. The experiment consisted of a sequence of magnetic field pulses at a repetition rate equal to the magnetic systems resonance frequency. We compared data obtained by this technique with conventional pulsed inductive microwave magnetometry. The results for damping and frequency response obtained by these two different methods coincide in the limit of a small angle excitation. However, when applying large amplitude field pulses, the magnetization had a non-linear response. We speculate that one possible cause of the nonlinearity is related to self-amplification of incoherence, known as the Suhl instabilities.