Antidamping-Torque-Induced Switching in Biaxial Antiferromagnetic Insulators

We investigate the current-induced switching of the N\'eel order in $\mathrm{NiO}(001)/\mathrm{Pt}$ heterostructures, 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 $1{0}^{7}\text{ }\text{ }\mathrm{A}/{\mathrm{cm}}^{2}$. The order-parameter switching is ascribed to the antiferromagnetic dynamics triggered by the (current-induced) antidamping torque, which orients the N\'eel order towards the direction of the writing current. This is in stark contrast to the case of antiferromagnets such as ${\mathrm{Mn}}_{2}\mathrm{Au}$ and CuMnAs, where fieldlike torques induced by the Edelstein effect drive the N\'eel switching, therefore resulting in an orthogonal alignment between the N\'eel 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.