Navigating Chiral Spin Architectures in Non-Collinear Antiferromagnetic Thin Films

TL;DR

This paper demonstrates how post-growth annealing produces high-quality noncollinear antiferromagnetic films that exhibit controllable chiral spin structure transitions, enabling potential applications in spintronics and neuromorphic devices.

Contribution

It reveals a method to produce near-defect-free films and uncovers a thickness-dependent transition between chiral magnetic states, advancing understanding of magnetic symmetry control.

Findings

Annealing yields structurally robust, near-defect-free films.

A critical thickness induces a transition between chiral spin states.

Chirality switching affects the sign and angular dependence of the Anomalous Hall effect.

Abstract

Noncollinear antiferromagnets offer much promise for antiferromagnetic spintronics and neuromorphic applications with a plethora of functional properties surpassing many competing magnetic systems. Films grown on mismatched substrates may relieve strain by the creation of slip-plane defects that strongly manipulate global physical properties important for application. This work demonstrates that a post growth annealing strategy results in near-defect-free, structurally robust films that reveal the underlying thermal evolution of the magnetic order symmetry. Beyond a critical film thickness, the spin structure transitions between two right-handed irreducible chiral representations via left-handed chiral ordering producing a striking change in the sign and angular dependence of the Anomalous Hall coefficient. The previously established mechanism of spin rotations in the (111) plane cannot fully explain the transition in applied magnetic field, and using a macrospin model this work finds that rotations along the chirality-inverting [1-10] direction are energetically preferable under certain conditions. These observations suggest that both left-handed and right-handed chiral order can be accessed in a single system, opening new routes to engineer devices by controlled switching of magnetic chirality allowing selection of associated functional properties as governed by symmetry.