Creation of domain-wall Skyrmions in chiral magnets

TL;DR

This paper investigates how magnetic Skyrmions can be captured and stabilized within domain walls in chiral magnets, revealing conditions for their creation, destruction, and pair formation through phase manipulation and energy considerations.

Contribution

It introduces the concept of creating stable DW-Skyrmion bound states by phase manipulation and explores pair creation mechanisms in chiral magnets.

Findings

Skyrmions are repelled by domain walls in ground states.

Phase rotation of the domain wall enables Skyrmion capture and stabilization.

Pair creation of Skyrmion-anti-DW-Skyrmion pairs is possible via a Kibble-like mechanism.

Abstract

We study the capture of a magnetic Skyrmion into a domain wall (DW) structure in chiral magnets and find that in the respective ground states of the DW and the Skyrmion, they repel each other. This means that an isolated magnetic Skyrmion cannot a priori enter the DW and become a DW-Skyrmion. However, rotating the DW's phase away from the stable phase may cause the successful capture and hence creation of a stable bound state of a magnetic Skyrmion and a DW: the DW-Skyrmion. At certain distances, the DW may also destroy the magnetic Skyrmion by inducing shrinkage of the latter. This happens as the isolated magnetic Skyrmion has negative DMI energy, whereas the DW-Skyrmion has positive DMI energy; in a finite range from the DW, the magnetic Skyrmion can be pushed to have vanishing DMI energy, for which it collapses to a point. En passant, we find the possibility of pair creation of a Skyrmion anti-DW-Skyrmion pair and a creation of more than one DW-Skyrmions by a Kibble-like mechanism.