Time-resolved imaging of pulse-induced magnetization reversal with a microwave assist field

TL;DR

This study provides the first direct, time-resolved imaging of microwave-assisted magnetization reversal, revealing the dominant role of spin wave dynamics and resonant frequencies in the switching process.

Contribution

It presents the first direct, time-resolved imaging of microwave-assisted magnetization reversal, highlighting the influence of spin wave dynamics and resonance effects.

Findings

Switching is dominated by spin wave dynamics.

Resonant microwave frequencies enhance reversal efficiency.

Identification of key frequencies involved in reversal.

Abstract

The reversal of the magnetization under the influence of a field pulse has been previously predicted to be an incoherent process with several competing phenomena such as domain wall relaxation, spin wave-mediated instability regions, and vortex-core mediated reversal dynamics. However, there has been no study on the direct observation of the switching process with the aid of a microwave signal input. We report a time-resolved imaging study of magnetization reversal in patterned magnetic structures under the influence of a field pulse with microwave assistance. The microwave frequency is varied to demonstrate the effect of resonant microwave-assisted switching. We observe that the switching process is dominated by spin wave dynamics generated as a result of magnetic instabilities in the structures, and identify the frequencies that are most dominant in magnetization reversal.