Microwave assisted magnetization reversal in single domain nanoelements

TL;DR

This study investigates microwave-assisted magnetization reversal in nanoscale elliptical NiFe magnets, demonstrating a significant reduction in coercive field when microwave frequency matches the resonance, supported by experimental and simulation data.

Contribution

It provides experimental and simulation evidence of coercive field reduction via microwave assistance in nanoscale magnets, highlighting resonance effects.

Findings

26% reduction in coercive field at resonance

Good agreement between experiments and simulations

Microwave frequency matching resonance enhances reversal efficiency

Abstract

We studied the microwave assisted magnetic reversal of 65 nm by 71 nm elliptical Ni80Fe20 nanomagnets. Hysteresis curves were measured by magneto-optical Kerr effect for a range of microwave frequencies and amplitudes. The coercive field Hc was reduced by 26% for an rf field of 0.08Hc when the microwave frequency coincided with the minimum of the experimentally determined ferromagnetic resonance frequency with varying dc field. The experimental results for the fractional reduction in Hc with rf field amplitude are in good agreement with numerical simulations for an array of interacting macrospins with a physically realistic shape anisotropy distribution