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arXiv · 2407.07731

Large spin-orbit torque in a-plane $\alpha$-Fe$_{2}$O$_{3}$/Pt bilayers

Igor Lyalin·Hantao Zhang·Justin Michel·Daniel Russell·Fengyuan Yang·Ran Cheng·Roland K. Kawakami
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Abstract

Realization of efficient spin-orbit torque switching of the N\'eel vector in insulating antiferromagnets is a challenge, often complicated by spurious effects. Quantifying the spin-orbit torques in antiferromagnet/heavy metal heterostructures is an important first step towards this goal. Here, we employ magneto-optic techniques to study damping-like spin-orbit torque (DL-SOT) in a-plane $\alpha$-Fe$_2$O$_3$ (hematite) with a Pt spin-orbit overlayer. We find that the DL-SOT efficiency is two orders of magnitude larger than reported in c- and r-plane hematite/Pt using harmonic Hall techniques. The large magnitude of DL-SOT is supported by direct imaging of current-induced motion of antiferromagnetic domains that happens at moderate current densities. Our study introduces a new method for quantifying spin-orbit torque in antiferromagnets with a small canted moment and identifies a-plane $\alpha$-Fe$_2$O$_3$ as a promising candidate to realize efficient SOT switching.

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Igor Lyalin, Hantao Zhang, Justin Michel, Daniel Russell, Fengyuan Yang, Ran Cheng, Roland K. Kawakami. 2024-07-10. Large spin-orbit torque in a-plane $\alpha$-Fe$_{2}$O$_{3}$/Pt bilayers. https://doi.org/10.1103/physrevlett.134.066701

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