Zero Field Antiferromagnetically Coupled Skyrmions and their Field-Driven Uncoupling in Composite Chiral Multilayers

TL;DR

This paper reports the engineering of composite antiferromagnetic skyrmions in multilayers, demonstrating their stability at zero external field and field-driven decoupling, which enhances their potential for robust spintronic applications.

Contribution

It introduces a novel composite AF chiral multilayer design that stabilizes skyrmions at zero field and enables their decoupling through external magnetic fields, advancing AF spin-texture control.

Findings

Stable AF skyrmions at zero external field.

Decoupling of skyrmions above the exchange field.

Enhanced stability and potential for spintronic devices.

Abstract

Antiferromagnetic (AF) skyrmions are topological spin structures with fully compensated, net-zero magnetization. Compared to their ferromagnetic (FM) skyrmion counterparts, their reduced stray field and enhanced electrical response can enable linear, high-throughput current-driven motion. However, their bubble-like character in conventional bilayer AFs limits their stability to fluctuations, leading to deformation and annihilation. Here we present the engineering of a composite AF chiral multilayer, wherein the interplay of AF and FM interlayer couplings generates compensated skyrmions with compact structures. High-resolution magnetic imaging and micromagnetic simulations show that the internal exchange field stabilizes AF skyrmions at zero external field with characteristics comparable to FM counterparts at 100 mT. Quantitative analyses establish their decoupling above the exchange field, yielding independent, spatially segregated textures in constituent chiral layers. This work provides a foundation to develop AF spin-textures with enhanced immunity, compatible with efficient readout and manipulation, with relevance to unconventional computing.