Stability and Dynamics of Skyrmion and Skyrmion Bags Explored under the Influence of Out-of-Plane Strain and Its Gradient

TL;DR

This study investigates how out-of-plane strain and its gradient influence the stability and dynamics of skyrmions and skyrmion bags in ferromagnetic thin films, revealing strain as a control mechanism for their movement.

Contribution

It provides new insights into controlling skyrmion dynamics using strain gradients, combining micromagnetic simulations with theoretical analysis.

Findings

Out-of-plane strain affects skyrmion stability.

Strain gradients can direct skyrmion movement.

Strain can counteract skyrmion Hall effects.

Abstract

Skyrmions as well as skyrmion bags in magnetic thin films are promising candidates for future high-density memory devices. The observation of skyrmion bags in liquid crystals and their predicted existence in ferromagnetic films has sparked theoretical studies on current induced dynamics of these topological charges. Here using micromagnetism, we study the impact of out of plane strain on the stability of skyrmion and skyrmion bags in ferromagnetic thin film. We further studied the current induced dynamics in the presence of out of plane strain gradient. We demonstrate that out of plane strain gradient direction with respect to the electron flow can be an efficient way to control the dynamics of topological charges. Specifically, the deflection of skyrmion bags correlates with their topological degree, and an appropriate strain gradient can counteract skyrmion Hall effects, enabling straight-line movement. Our micromagnetic simulations align well with theoretical predictions from the Thiele equation.