Fig. 1: Characterization and magnetotransport in antiferromagnetic thin-film FeRh.

a Schematic of the FeRh lattice with epitaxial matching to an MgO substrate. ϕ is the orientation of the external magnetic field, H, relative to the current along a well-defined crystallographic direction. The behavior of the antiferromagnetic (AFM) order is displayed in the limits of both low and high magnetic fields. An increasing field cants the AFM moments into a non-collinear configuration, and a ferromagnetic moment is generated on the Rh sublattice. The rotation of all magnetization orientations is illustrated as H rotates. Note that the theoretically expected orthorhombic distortion of the FeRh is not indicated in the schematic. b Electronic band structure calculations from density functional theory are shown for the orthorhombic collinear AFM structure (top panel) as well as the non-collinear AFM structure with Rh moment oriented along the [100] direction (bottom panel). c The field-dependent magnetoresistance is shown when the field is swept at ϕ = 0° and ϕ = 90° at T = 10 K. The magnetoresistance does not saturate in high-magnetic fields, and the lower plot demonstrates a hysteretic anisotropic magnetoresistance peak at low fields consistent with the presence of residual ferromagnetism. The black arrows denote the direction of the external field sweep. d The anomalous Hall effect in both the ferro- and antiferromagnetic phase of FeRh are shown at T = 350 K and 110 K respectively. The zero-field anomalous voltage, better seen in the lower plot, indicates the presence of a Berry phase induced by strong spin-orbit coupling the material and is concomitant with the presence of a topological response23,24,48,49.