Antidamping-Torque-Induced Switching in Biaxial Antiferromagnetic Insulators

We investigate the current-induced switching of the Neel order in NiO(001)/Pt heterostractures, which is manifested electrically via the spin Hall magnetoresistance. Significant reversible changes in the longitudinal and transverse resistances are found at room temperature for a current threshold lying in the range of 10(7) A/cm(2). The order-parameter switching is ascribed to the antiferromagnetic dynamics triggered by the (current-induced) antidamping torque, which orients the Neel order towards the direction of the writing current. This is in stark contrast to the case of antiferromagnets such as Mn2Au and CuMnAs, where fieldlike torques induced by the Edelstein effect drive the Neel switching, therefore resulting in an orthogonal alignment between the Neel order and the writing current. Our findings can be readily generalized to other biaxial antiferromagnets, providing broad opportunities for all-electrical writing and readout in antiferromagnetic spintronics.