Size and shape of skyrmions for variable Dzyaloshinskii-Moriya interaction and uniaxial anisotropy

TL;DR

This study uses micromagnetic simulations to explore how Dzyaloshinskii-Moriya interaction strength, uniaxial anisotropy, and element shape influence skyrmion formation and morphology in ferromagnetic nanostructures.

Contribution

It reveals the combined effects of D, K, and shape on skyrmion existence and morphology, highlighting conditions that hinder or promote skyrmion formation.

Findings

Skyrmion formation depends on specific D and K regimes.

Large D and small K lead to non-spherical skyrmionic phases.

Shape significantly influences the magnetic states and skyrmion morphology.

Abstract

We have performed micromagnetic simulations to study the formation of skyrmions in ferromagnetic elements with different shapes having perpendicular anisotropy. The strength of Dzyaloshinskii-Moriya interaction (D) and uniaxial anisotropy (K) are varied to elucidate the regime in which skyrmion formation can take place. It is found that for a certain combination of D and K skyrmion formation does not happen. Further we also observed that for large D and small K values, finite size effect dominates which in turn hinders formation of typical N'eel (spherical) skyrmions. However the resulting magnetic phase is skyrmionic in nature and has different shape. We also have found that the shape of the magnetic nano element has a significant role in determining the final magnetic state in addition to the competing D and K values.