Dynamics of ferromagnetic nanomagnets with vortex or single-domain configuration

TL;DR

This paper investigates the dynamic switching behaviors of ferromagnetic nanomagnets with vortex and single-domain states using micromagnetic simulations, revealing fast, independent control of vortex properties and spin wave excitations.

Contribution

It provides new insights into the fast, independent switching of vortex vorticity and polarity, and details the spin wave excitation in single-domain nanomagnets.

Findings

Vorticity and polarity can be switched independently within 50-100 ps.

Vortex structures exhibit fast switching dynamics.

Single-domain nanomagnets show homogeneous behavior followed by spin wave excitation.

Abstract

We study the dynamics of flat circular permalloy nanomagnets for 1.) magnetic vortex and 2.) single-domain configurations, using micromagnetic simulation. Dynamical studies for isolated vortex structures show that both the vorticity and the central polarity of the out-of-plane component can be switched fast (50-100 ps) and independently. Micromagnetic simulations of the switching process in thin cylindrical Permalloy (Py) nanoparticles with an initial stable single-domain state show nearly homogeneous single-domain behaviour followed by excitation of spin waves.