Cycloidal versus skyrmionic states in mesoscopic chiral magnets

TL;DR

This study explores how confinement influences cycloidal and skyrmionic states in thin chiral magnetic films, revealing multiple stable cycloidal states with varying periods and the stability of skyrmions depending on film dimensions.

Contribution

It provides a phase diagram showing the stability of various magnetic states in confined geometries, highlighting the impact of size on cycloid periods and skyrmion stability.

Findings

Multiple cycloidal states with different periods are stable in confined films.

The cycloid period depends on both Dzyaloshinskii-Moriya interaction and film dimensions.

Skyrmionic states are stable but have higher energy than cycloidal states.

Abstract

When subjected to the interfacially induced Dzyaloshinskii-Moriya interaction, the ground state in thin ferromagnetic films with high perpendicular anisotropy is cycloidal. The period of this cycloidal state depends on the strength of the Dzyaloshinskii-Moriya interaction. In this work, we have studied the effect of confinement on the magnetic ground state and excited states, and we determined the phase diagram of thin strips and thin square platelets by means of micromagnetic calculations. We show that multiple cycloidal states with different periods can be stable in laterally confined films, where the period of the cycloids does not depend solely on the Dzyaloshinskii-Moriya interaction strength but also on the dimensions of the film. The more complex states comprising skyrmions are also found to be stable, though with higher energy.