Magnetic vortex as a ground state for sub-micron antiferromagnetic particles

TL;DR

This paper demonstrates that submicron antiferromagnetic particles with axisymmetric shapes can naturally host a magnetic vortex ground state, featuring unique topological and dynamic properties, including high-frequency localized modes.

Contribution

It introduces the concept of a magnetic vortex as the ground state in submicron antiferromagnetic particles with axisymmetric shapes, revealing new topological and dynamic phenomena.

Findings

Vortex ground state exists in submicron antiferromagnetic particles.

High-frequency localized modes are present near the vortex core.

Vortex state exhibits topologically non-trivial magnetization distribution.

Abstract

For submicron particles shaped as any axisymmetric body and made with standard canted antiferromagnet like hematite or iron borate, the ground state may comprise of a magnetic vortex with topologically non-trivial distribution of the sublattice magnetization $\vec{l}$ and planar coreless vortex-like structure for the net magnetization $\vec{M}$. For antiferromagnetic particles in the vortex state, in addition to low-frequency modes, there are high frequency modes with frequencies over the range of hundreds gigahertz, including a mode localized in the region of the radius 30-40 nm near a vortex core.