Dynamic origin of azimuthal modes splitting in vortex-state magnetic dots

TL;DR

This paper develops a spin wave theory explaining the experimentally observed frequency splitting of azimuthal modes in vortex-state magnetic dots, attributing it to dipolar hybridization of specific modes and matching experimental data.

Contribution

It introduces a theoretical model that explains the origin of azimuthal mode splitting in vortex magnetic dots, aligning with experimental observations.

Findings

Frequency splitting is proportional to the ratio of dot thickness to radius.

The model's predictions agree quantitatively with Kerr experiment results.

Hybridization of three specific spin wave modes causes the splitting.

Abstract

A spin wave theory explaining experimentally observed frequency splitting of dynamical excitations with azimuthal symmetry of a magnetic dot in a vortex ground state is developed. It is shown that this splitting is a result of the dipolar hybridization of three spin wave modes of a dot having azimuthal indices |m|=1: two high-frequency azimuthal excitation modes of the in-plane part of the vortex with indices m = +/-1 and a low-frequency m= +1 gyrotropic mode describing the translational motion of the vortex core. The analytically calculated magnitude of the frequency splitting is proportional to the ratio of the dot thickness to its radius and quantitatively agrees with the results of time resolved Kerr experiments.