Microwave assisted resonant domain wall nucleation in permalloy nanowires

TL;DR

This study demonstrates that microwave fields can efficiently assist domain wall nucleation in permalloy nanowires, significantly reducing the required magnetic field and enabling precise control through resonance effects.

Contribution

It introduces a system to study microwave-assisted domain wall nucleation and reveals a resonance-dependent reduction in nucleation fields in permalloy nanowires.

Findings

Microwave fields lower the nucleation field compared to pulse fields.

A resonance peak at the ferromagnetic resonance frequency enhances nucleation.

Switching field distribution is smaller with microwave assistance.

Abstract

We have designed a system to study microwave assisted domain wall nucleation in permalloy nanowires. We find a substantial decrease in the nucleation field when microwave fields are applied, in comparison to pulse fields. A clear resonance peak is observed in the frequency dependence of the nucleation field, which coincides with the uniform mode ferromagnetic resonance frequency. Owing to the well-defined nucleation process, the switching field distribution is small in contrast to previous reports. Our results show that localized microwave field provides an efficient tool for injecting domain walls into magnetic nanowires.