New Reversal Mode in Exchange Coupled Antiferromagnetic/Ferromagnetic Disks: Distorted Viscous Vortex

TL;DR

This paper introduces a novel reversal mode in exchange coupled antiferromagnetic/ferromagnetic disks, where vortices are distorted and viscously dragged, revealing new physics and potential applications in nanostructures.

Contribution

It reports a new vortex reversal mode involving distortion and viscous dragging in exchange coupled antiferromagnetic/ferromagnetic microdots, expanding understanding of vortex physics.

Findings

Vortex distortion occurs near the interface.

Asymmetries in annihilation and nucleation fields are observed.

The reversal mode involves viscous dragging due to uncompensated spins.

Abstract

Magnetic vortices have generated intense interest in recent years due to their unique reversal mechanisms, fascinating topological properties, and exciting potential applications. Additionally, the exchange coupling of magnetic vortices to antiferromagnets has also been shown to lead to a range of novel phenomena and functionalities. Here we report a new magnetization reversal mode of magnetic vortices in exchange coupled Ir20Mn80/Fe20Ni80 microdots: distorted viscous vortex reversal. Contrary to the previously known or proposed reversal modes, the vortex is distorted close to the interface and viscously dragged due to the uncompensated spins of a thin antiferromagnet, which leads to unexpected asymmetries in the annihilation and nucleation fields. These results provide a deeper understanding of the physics of exchange coupled vortices and may also have important implications for applications involving exchange coupled nanostructures.