Enhanced skyrmion motion via strip domain wall

TL;DR

This paper demonstrates that the presence of a strip domain wall in magnetic nanowires enhances skyrmion motion by increasing the annihilation current and preventing edge annihilation, enabling faster skyrmion dynamics.

Contribution

It reveals how a Nél domain wall interacts with skyrmions, increasing their stability and speed, a novel insight into magnetic texture interplay.

Findings

Domain wall increases skyrmion annihilation current.

Enhanced skyrmion speed due to domain wall presence.

Broken axisymmetry causes longitudinal repulsive force.

Abstract

When magnetic skyrmions move under spin orbit torque in magnetic nanowires, they experience a skyrmion Hall effect, which pushes them towards the nanowire edge where they risk being annihilated; this puts an upper limit on how fast they can be driven. However, the same magnetic multilayer harboring skyrmions can sustain a N\'eel-type strip domain wall along the nanowire length, potentially keeping the skyrmions separated from the edge. Here we study the interplay between current driven skyrmions and domain walls and find that they increase the annihilation current and allow the skyrmions to move faster. Based on the Thiele formalism, we confirm that the emergent longitudinal repulsive force and the modified energy landscape linked to the domain wall are responsible for the enhanced skyrmion motion. Furthermore, we identify that the longitudinal repulsive force emerges because of the broken axisymmetry in the local magnetization in front of the skyrmion. Our study uncovers key aspects in the interplay between two topological magnetic textures from different homotopy groups and may inspire new device concepts.