Unidirectional Magnetoresistance in Antiferromagnet/Heavy-Metal Bilayers

Among different electrical probes to read out magnetic order, unidirectional magnetoresistance (UMR), where the resistance changes with the current direction reversal, can provide valuable understanding of the transport properties of spin-orbit coupled systems. However, UMR has not been expected or observed in antiferromagnets before. In this talk, we report that a sizable UMR can arise in an antiferromagnetic system, specifically in the antiferromagnetic phase of a FeRh/Pt bilayer [1]. The observed UMR exhibits a sign change and then increases strongly with an applied magnetic field, in contrast to the UMRs observed in ferromagnetic and non-magnetic systems. We attribute this UMR to the combined effects of the Rashba spin-orbit coupling at the FeRh/Pt interface and the antiferromagnetic spin canting. Our findings motivate the growing fields of antiferromagnetic spintronics and suggest a route to the development of tunable antiferromagnet-based spintronics devices.

[1] S. Shim, M. Mehraeen et al., Physical Review X 12, 021069 (2022).