The effect of spin currents on the magnetic order of insulating antiferromagnets (AFMs) is of fundamental interest and can enable new applications. Toward this goal, characterizing the spin-orbit torques (SOT) associated with AFM/heavy metal (HM) interfaces is important. Here we report the full angular dependence of the harmonic Hall voltages in a predominantly easy-plane AFM, epitaxial c-axis oriented α-Fe2O3 films, with an interface to Pt. By modeling the harmonic Hall signals together with the α-Fe2O3 magnetic parameters, we determine the amplitudes of field-like and damping-like SOT. Out-of-plane field scans are shown to be essential to determining the damping-like component of the torques. In contrast to ferromagnetic/heavy metal heterostructures, our results demonstrate that the field-like torques are significantly larger than the damping-like torques, which we correlate with the presence of a large imaginary component of the interface spin-mixing conductance. Our work demonstrates a direct way of characterizing SOT in AFM/HM heterostructures.
@article{arxiv.2112.12238,
title = {Quantifying Spin-Orbit Torques in Antiferromagnet/Heavy Metal Heterostructures},
author = {Egecan Cogulu and Hantao Zhang and Nahuel N. Statuto and Yang Cheng and Fengyuan Yang and Ran Cheng and Andrew D. Kent},
journal= {arXiv preprint arXiv:2112.12238},
year = {2022}
}