Dynamic transformation between a skyrmion string and a bimeron string in a layered frustrated system

TL;DR

This paper investigates the static and dynamic behaviors of 3D skyrmion and bimeron strings in layered frustrated magnetic systems, revealing their transformation capabilities and potential for spintronic applications.

Contribution

It demonstrates the current-induced transformation between skyrmion and bimeron strings in layered frustrated magnets, a novel physical phenomenon for spin textures.

Findings

Skyrmion strings are more stable than Néel-type in layered systems.

Current can induce skyrmion to bimeron transformation.

Bimeron strings rotate stably and revert to skyrmions when current stops.

Abstract

Frustrated topological spin textures have unique properties that may enable novel spintronic applications, such as helicity-based information storage and computing. Here, we report the statics and current-induced dynamics of two-dimensional (2D) pancake skyrmions in a stack of weakly coupled frustrated magnetic monolayers, which form a three-dimensional (3D) skyrmion string. The Bloch-type skyrmion string is energetically more stable than its N\'eel-type counterpart. It can be driven into translational motion by the dampinglike spin-orbit torque and shows the damping-dependent skyrmion Hall effect. Most notably, the skyrmion string can be transformed to a dynamically stable bimeron string by the dampinglike spin-orbit torque. The current-induced bimeron string rotates stably with respect to its center, which can spontaneously transform back to a skyrmion string when the current is switched off. Our results reveal unusual physical properties of 3D frustrated spin textures, and may open up different possibilities for spintronic applications based on skyrmion and bimeron strings.