Skyrmions in thin films with easy-plane magnetocrystalline anisotropy

TL;DR

This paper demonstrates the existence of chiral skyrmions as stable or metastable states in thin films with easy-plane anisotropy, using comprehensive micromagnetic simulations that explore parameter spaces.

Contribution

It provides the first systematic numerical analysis of skyrmion stability in easy-plane anisotropic thin films, challenging previous analytical predictions.

Findings

Skyrmions are metastable and sometimes stable in easy-plane anisotropic thin films.

Skyrmion size increases with the strength of easy-plane anisotropy.

The stability depends on magnetic field and anisotropy parameters.

Abstract

We demonstrate that chiral skyrmionic magnetization configurations can be found as the minimum energy state in B20 thin film materials with easy-plane magnetocrystalline anisotropy with an applied magnetic field perpendicular to the film plane. Our observations contradict results from prior analytical work, but are compatible with recent experimental investigations. The size of the observed skyrmions increases with the easy-plane magnetocrystalline anisotropy. We use a full micromagnetic model including demagnetization and a three-dimensional geometry to find local energy minimum (metastable) magnetization configurations using numerical damped time integration. We explore the phase space of the system and start simulations from a variety of initial magnetization configurations to present a systematic overview of anisotropy and magnetic field parameters for which skyrmions are metastable and global energy minimum (stable) states.