Vortex dynamics in confined stratified conditions

TL;DR

This study investigates the linear spin dynamics of vortex states in Permalloy dots under stratified magnetic fields, revealing distinct regimes, symmetry-breaking effects, and orientation-dependent responses with potential implications for confined vortex systems.

Contribution

It provides experimental and simulation evidence of dynamic regimes and eigenmode behaviors in vortex states under stratified conditions, highlighting symmetry-breaking effects and orientation dependence.

Findings

Existence of stable and metastable vortex dynamic regimes

Symmetry breaking causes eigenmode frequency splitting

Metastable state response depends on rf and magnetic field orientation

Abstract

We report on linear spin dynamics in the vortex state of the Permalloy dots subjected to stratified (magnetic) field. We demonstrate experimentally and by simulations the existence of two distinct dynamic regimes corresponding to the vortex stable and metastable states. Breaking cylindrical symmetry leads to unexpected eigenmodes frequency splitting in the stable state and appearance of new eigenmodes in the metastable state above the vortex nucleation field. Dynamic response in the metastable state strongly depends on relative orientation of the external rf pumping and the bias magnetic fields. These findings may be relevant for different vortex states in confined and stratified conditions.