Controlled creation and stability of k{\pi}-skyrmions on a discrete lattice

TL;DR

This study investigates the sizes, stability, and switching mechanisms of kπ-skyrmions on a discrete lattice using computational methods, revealing their critical fields, activation energies, and a novel magnetic field reversal switching technique.

Contribution

It introduces a detailed computational analysis of kπ-skyrmions' stability and proposes a new method for switching skyrmion order via magnetic field reversal.

Findings

Critical magnetic fields for skyrmion collapse are similar for 2π and 3π skyrmions, lower than for 1π.

Activation energy does not decrease monotonically with increasing k, can be higher for 3π than 2π.

Magnetic field reversal can switch skyrmion order in finite-sized samples.

Abstract

We determine sizes and activation energies of k{\pi}-skyrmions on a discrete lattice using the Landau- Lifshitz-Gilbert equation and the geodesic nudged elastic band method. The employed atomic material parameters are based on the skyrmionic material system Pd/Fe/Ir(111). We find that the critical magnetic fields for collapse of the 2{\pi}-skyrmion and 3{\pi}-skyrmion are very close to each other and considerably lower than the critical field of the 1{\pi}-skyrmion. The activation energy protecting the structures does not strictly decrease with increasing k as it can be larger for the 3{\pi}-skyrmion than for the 2{\pi}-skyrmion depending on the applied magnetic field. Furthermore, we propose a method of switching the skyrmion order k by a reversion of the magnetic field direction in samples of finite size.