All-optical magneto-thermo-elastic skyrmion motion

TL;DR

This paper predicts that focused laser beams can controllably move magnetic skyrmions on surfaces through thermo-elastic effects, enabling all-optical manipulation of skyrmions for potential device applications.

Contribution

It introduces a dynamical magneto-thermo-elastic model demonstrating laser-induced skyrmion motion with significant velocities, including in ferromagnetic and antiferromagnetic materials.

Findings

Skyrmions can be moved up to 80 m/s using laser-induced thermo-elastic effects.

The mechanism works for both ferromagnetic and antiferromagnetic skyrmions.

Surface roughness does not prevent skyrmion motion.

Abstract

It is predicted magnetic skyrmions can be controllably moved on surfaces using a focused laser beam. Here an absorbed power of the order 1 mW, focused to a spot-size of the order 10 $\mu$m, results in a local temperature increase of around 50 K, and a local perpendicular strain of the order 10$^{-3}$ due to the thermo-elastic effect. For positive magneto-elastic coupling this generates a strong attractive force on skyrmions due to the magneto-elastic effect. The resultant motion is dependent on forces due to i) gradients in the local strain-induced magnetic anisotropy, ii) gradients in the effective anisotropy due to local temperature gradients, and magnetic parameters temperature dependences, and iii) Magnus effect acting on objects with non-zero topological number. Using dynamical magneto-thermo-elastic modelling, it is predicted skyrmions can be moved with significant velocities (up to 80 m/s shown), both for ferromagnetic and antiferromagnetic skyrmions, even in the presence of surface roughness. This mechanism of controllably moving single skyrmions in any direction, as well as addressing multiple skyrmions in a lattice, offers a new approach to constructing and studying skyrmionic devices with all-optical control.