  Unidirectional magnetoresistance (UMR) has been observed in a variety of
stacks with ferromagnetic/spin Hall material bilayer structures. In this work,
we reported UMR in antiferromagnetic insulator Fe2O3/Pt structure. The UMR has
a negative value, which is related to interfacial Rashba coupling and band
splitting. Thickness-dependent measurement reveals a potential competition
between UMR and the unidirectional spin Hall magnetoresistance (USMR). This
work revealed the existence of UMR in antiferromagnetic insulators/heavy metal
bilayers and broadens the way for the application of antiferromagnet-based
spintronic devices.
