Unidirectional Spin Hall Magnetoresistance in Antiferromagnetic Heterostructures

Yang Cheng; Junyu Tang; Justin J Michel; Su Kong Chong; Fengyuan Yang; Ran Cheng; Kang L Wang

doi:10.1103/PhysRevLett.130.086703

Unidirectional Spin Hall Magnetoresistance in Antiferromagnetic Heterostructures

Phys Rev Lett. 2023 Feb 24;130(8):086703. doi: 10.1103/PhysRevLett.130.086703.

Authors

Yang Cheng¹, Junyu Tang², Justin J Michel³, Su Kong Chong¹, Fengyuan Yang³, Ran Cheng^{2

4}, Kang L Wang¹

Affiliations

¹ Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
² Department of Physics and Astronomy, University of California, Riverside, California 92521, USA.
³ Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.
⁴ Department of Electrical and Computer Engineering, University of California, Riverside, California 92521, USA.

PMID: 36898091
DOI: 10.1103/PhysRevLett.130.086703

Abstract

Unidirectional spin Hall magnetoresistance (USMR) has been widely reported in the heavy metal/ferromagnet bilayer systems. We observe the USMR in Pt/α-Fe_{2}O_{3} bilayers where the α-Fe_{2}O_{3} is an antiferromagnetic (AFM) insulator. Systematic field and temperature dependent measurements confirm the magnonic origin of the USMR. The appearance of AFM-USMR is driven by the imbalance of creation and annihilation of AFM magnons by spin orbit torque due to the thermal random field. However, unlike its ferromagnetic counterpart, theoretical modeling reveals that the USMR in Pt/α-Fe_{2}O_{3} is determined by the antiferromagtic magnon number with a non-monotonic field dependence. Our findings extend the generality of the USMR which pave the ways for the highly sensitive detection of AFM spin state.