Observation of a non-reciprocal skyrmion Hall effect of hybrid chiral skyrmion tubes in synthetic antiferromagnetic multilayers

TL;DR

This paper reports the discovery of a non-reciprocal skyrmion Hall effect in hybrid chiral skyrmion tubes within synthetic antiferromagnetic multilayers, revealing new dynamics linked to their internal chirality transitions.

Contribution

It demonstrates the non-reciprocal skyrmion Hall effect in hybrid chiral skyrmion tubes and explains its origin through theoretical modeling of helicity oscillations.

Findings

Non-reciprocal skyrmion Hall effect observed in hybrid chiral skyrmion tubes.

The effect can be tuned by magnetic compensation levels.

Helicity oscillations drive the non-reciprocity during current-induced motion.

Abstract

A hybrid chiral skyrmion tube is a well-known example of a 3D topological spin texture, exhibiting an intriguing chirality transition along the thickness direction. This transition progresses from left-handed to right-handed N\'eel-type chirality, passing through a Bloch-type intermediate state. Such an exotic spin configuration potentially exhibits distinctly different dynamics from that of the common skyrmion tube that exhibits a homogeneous chirality; yet these dynamics have not been ascertained so far. Here we reveal the distinct features of current-induced dynamics that result from the hybrid chiral skyrmion tube structure in synthetic antiferromagnetic (SyAFM) multilayers. Strikingly, the SyAFM hybrid chiral skyrmion tubes exhibit a non-reciprocal skyrmion Hall effect in the flow regime. The non-reciprocity can even be tuned by the degree of magnetic compensation in the SyAFM systems. Our theoretical modeling qualitatively corroborates that the non-reciprocity stems from the dynamic oscillation of skyrmion helicity during its current-induced motion. The findings highlight the critical role of the internal degrees of freedom of these complex skyrmion tubes for their current-induced dynamics.