Temperature dependence of the anisotropic magnetoresistance of the metallic antiferromagnet Fe₂As

Electrical readout of metallic antiferromagnet (AF) memories is typically realized by measuring the anisotropic magnetoresistance (AMR), but the mechanisms for enhanced AMR are not yet established. We study AMR of single crystals of AF Fe₂As from T=5 K to above the Néel temperature, T_N ∼ 353 K. With an applied magnetic field B rotating in the (001) plane, we observe a peak-to-peak AMR change of 1.3% for B>1 T at T=5 K, one order of magnitude larger than in CuMnAs, a widely studied candidate for AF spintronics. The AMR varies strongly with temperature, decreasing by a factor of ∼ 10 at T∼ 200 K, and depends on the residual resistance. Our results suggest large AMR in easy-plane AFs may require Néel temperatures that greatly exceed room temperature.