Suppression of the skyrmion Hall effect in synthetic ferrimagnets with gradient magnetization

TL;DR

This study demonstrates that introducing a gradient in saturation magnetization within synthetic ferrimagnetic materials can effectively suppress the skyrmion Hall effect, enhancing the potential for practical skyrmion-based spintronic devices.

Contribution

The paper presents a novel approach of using a magnetization gradient to control and suppress the skyrmion Hall effect in synthetic ferrimagnets, supported by micromagnetic simulations and theoretical analysis.

Findings

Magnetization gradient modulates skyrmion Hall angle.

Ferrimagnetic skyrmions are more sensitive to Ms variations than ferromagnetic ones.

Ms gradient alters skyrmion size and dynamics, reducing the SkHE.

Abstract

Magnetic skyrmions are promising building blocks for future spintronic devices. However, the skyrmion Hall effect (SkHE) remains an obstacle for practical applications based on the in-line transport of skyrmions. Here, we numerically study the static properties and current-driven dynamics of synthetic ferrimagnetic skyrmions. Inspired by graded-index magnonics, we introduce a linear gradient of saturation magnetization (Ms) in the skyrmion-hosting sample, which effectively modulates the skyrmion Hall angle and suppresses the SkHE. Micromagnetic simulations reveal that ferrimagnetic skyrmions could exhibit greater susceptibility to the variation of Ms as compared to their ferromagnetic counterparts. The Thiele analysis is also applied to support the simulation results, which elucidates that the Ms gradient dynamically modifies the intrinsic normalized size of skyrmions, consequently impacting the SkHE. Our results pave the way to the graded-index skyrmionics, which offers novel insights for designing ferrimagnet-based skyrmionic devices.