Current-driven dynamics and inhibition of the skyrmion Hall effect of ferrimagnetic skyrmions in GdFeCo films

TL;DR

This study demonstrates the stabilization and current-driven motion of ferrimagnetic skyrmions in GdFeCo films, showing reduced skyrmion Hall effect and potential for advanced spintronic applications.

Contribution

It provides experimental evidence of ferrimagnetic skyrmions' dynamics and their reduced Hall effect, confirming theoretical predictions in a practical material system.

Findings

Skyrmions in Gd and FeCo layers are antiferromagnetically exchange-coupled.

Ferrimagnetic skyrmions move at ~50 m/s with a skyrmion Hall angle of ~20°.

Experimental validation of theoretical models on ferrimagnetic skyrmion dynamics.

Abstract

Magnetic skyrmions are swirling magnetic textures with novel characteristics suitable for future spintronic and topological applications. Recent studies confirmed the room-temperature stabilization of skyrmions in ultrathin ferromagnets. However, such ferromagnetic skyrmions show undesirable topological effect, the skyrmion Hall effect, which leads to their current-driven motion towards device edges, where skyrmions could easily be annihilated by topographic defects. Recent theoretical studies have predicted enhanced current-driven behaviour for antiferromagnetically exchange-coupled skyrmions. Here we present the stabilization of these skyrmions and their current-driven dynamics in ferrimagnetic GdFeCo films. By utilizing element-specific X-ray imaging, we find that the skyrmions in the Gd and FeCo sublayers are antiferromagnetically exchange-coupled. We further confirm that ferrimagnetic skyrmions can move at a velocity of ~50 m s-1 with reduced skyrmion Hall angle, {\theta}SkHE ~20{\deg}. Our findings open the door to ferrimagnetic and antiferromagnetic skyrmionics while providing key experimental evidences of recent theoretical studies.