Optimal control of vortex core polarity by resonant microwave pulses

TL;DR

This paper demonstrates the coherent control of vortex core polarity in magnetic nano-disks using resonant microwave pulses, revealing insights into vortex dynamics and dissipation in non-linear regimes.

Contribution

It introduces a method to control vortex core polarity with microwave pulses and infers vortex core decay times, advancing understanding of non-linear magnetic dissipation.

Findings

Successful control of vortex core polarity with microwave pulses

Decay time of vortex core in large oscillations is over twice shorter

Highlights non-linear behavior of magnetic dissipation

Abstract

In a vortex-state magnetic nano-disk, the static magnetization is curling in the plane, except in the core region where it is pointing out-of-plane, either up or down leading to two possible stable states of opposite core polarity p. Dynamical reversal of p by large amplitude motion of the vortex core has recently been demonstrated experimentally,raising fundamental interest for potential application in magnetic storage devices. Here we demonstrate coherent control of p by single and double microwave pulse sequences, taking advantage of the resonant vortex dynamics in a perpendicular bias magnetic field. Optimization of the microwave pulse duration required to switch p allows to experimentally infer the characteristic decay time of the vortex core in the large oscillation regime. It is found to be more than twice shorter than in the small oscillation regime, raising the fundamental question of the non-linear behaviour of magnetic dissipation.