Creation of domain-wall skyrmions in chiral magnets with Landau-Lifshitz-Gilbert dynamics and demagnetization

TL;DR

This paper investigates how magnetic skyrmions can be absorbed into domain walls in chiral magnets, mapping out creation and annihilation conditions, and explores the potential for skyrmion pair production via a domain-wall-based Kibble-Zurek mechanism.

Contribution

It provides a comprehensive phase diagram of skyrmion-domain wall interactions considering demagnetization effects and proposes a novel setup for skyrmion pair creation through domain wall instabilities.

Findings

Absorption of skyrmions into domain walls depends on DMI type and demagnetization.

Phase diagrams show conditions for skyrmion creation, repulsion, or annihilation.

Theoretical possibility of generating skyrmion-anti-skyrmion pairs via domain wall instabilities.

Abstract

Absorption of an isolated bulk magnetic skyrmion into an empty domain wall in a chiral ferromagnetic system is studied using the Landau-Lifshitz-Gilbert equation with and without the demagnetization effect taken into account. The full phase diagram of creation versus repulsion or annihilation is mapped out in case of both Bloch-type and N\'eel-type DMI, with and without demagnetization. Finally, the unstable domain wall, realizable with a setup of several external magnets, contains the theoretical possibility of producing a 1-dimensional version of the Kibble-Zurek mechanism, which in turn can create a number of skyrmion-anti-skyrmion pairs engulfed in the domain wall: We denote them domain-wall-skyrmion-anti-domain-wall-skyrmion pairs.