Efficient Spin-Orbit Torques in an Antiferromagnetic Insulator with Tilted Easy Plane

TL;DR

This paper demonstrates efficient spin-orbit torque-induced switching in a tilted easy plane antiferromagnetic insulator, enabling practical bipolar switching and advancing understanding of antiferromagnetic dynamics for spintronics.

Contribution

It introduces a novel tilted easy plane configuration in e2O3 that allows robust and efficient control of the Ne9el vector via spin-orbit torques, with potential for device applications.

Findings

Achieved bipolar switching with positive and negative currents in e2O3

Demonstrated spin-orbit torque effect comparable to ferromagnets

Provided insights into switching dynamics in antiferromagnets

Abstract

Electrical manipulation of spin textures inside antiferromagnets represents a new opportunity for developing spintronics with superior speed and high device density. Injecting spin currents into antiferromagnets and realizing efficient spin-orbit-torque-induced switching is however still challenging due to the complicated interactions from different sublattices. Meanwhile, because of the diminishing magnetic susceptibility, the nature and the magnitude of current-induced magnetic dynamics remain poorly characterized in antiferromagnets, whereas spurious effects further complicate experimental interpretations. In this work, by growing a thin film antiferromagnetic insulator, {\alpha}-Fe2O3, along its non-basal plane orientation, we realize a configuration where an injected spin current can robustly rotate the N\'eel vector within the tilted easy plane, with an efficiency comparable to that of classical ferromagnets. The spin-orbit torque effect stands out among other competing mechanisms and leads to clear switching dynamics. Thanks to this new mechanism, in contrast to the usually employed orthogonal switching geometry, we achieve bipolar antiferromagnetic switching by applying positive and negative currents along the same channel, a geometry that is more practical for device applications. By enabling efficient spin-orbit torque control on the antiferromagnetic ordering, the tilted easy plane geometry introduces a new platform for quantitatively understanding switching and oscillation dynamics in antiferromagnets.