Angle-resolved spin-torque ferromagnetic resonance measurements are carried out in heterostructures consisting of Py (Ni81Fe19) and a noncollinear antiferromagnetic quantum material γ−IrMn3. The structural characterization reveals that γ−IrMn3 is polycrystalline in nature. A large exchange bias of 158~Oe is found in Py/γ−IrMn3 at room temperature, while γ−IrMn3/Py and Py/Cu/γ−IrMn3 exhibited no exchange bias. Regardless of the exchange bias and stacking sequence, we observe a substantial unconventional out-of-plane anti-damping torque when γ−IrMn3 is in direct contact with Py. The magnitude of the out-of-plane spin-orbit torque efficiency is found to be twice as large as the in-plane spin-orbit torque efficiency. The unconventional spin-orbit torque vanishes when a Cu spacer is introduced between Py and γ−IrMn3, indicating that the unconventional spin-orbit torque in this system originates at the interface. These findings are important for realizing efficient antiferromagnet-based spintronic devices via interfacial engineering.
@article{arxiv.2305.04596,
title = {Interfacial origin of unconventional spin-orbit torque in Py/$\gamma-$IrMn$_{3}$},
author = {Akash Kumar and Pankhuri Gupta and Niru Chowdhury and Kacho Imtiyaz Ali Khan and Utkarsh Shashank and Surbhi Gupta and Yasuhiro Fukuma and Sujeet Chaudhary and Pranaba Kishor Muduli},
journal= {arXiv preprint arXiv:2305.04596},
year = {2023}
}