Spin-orbit torque oscillator driven by anomalous Hall effect

Giant antidamping spin-orbit torques (SOTs) in multilayers of ferromagnetic (FM) and non-magnetic (NM) materials can be used to drive auto-oscillatory magnetization dynamics in a spintronics device know as a spin-orbit torque oscillator (SOTO). SOTOs are nanoscale sources of microwave radiation, and harnessing their highly non-linear dynamics holds promise for neuromorphic computing. Conventional SOTO devices utilize spin Hall currents originating from spin-orbit coupling within NM layers. In this talk, we report the discovery of a giant self-generated antidamping spin-orbit torque linked to the anomalous Hall effect in a FM metal that is large enough to overcome the natural damping of the FM and thereby realize a new kind of SOTO. To demonstrate the operation of SOTOs driven by the anomalous Hall SOT, we fabricated NM₁|FM|NM₂ nanowire SOTO devices and studied their current-driven auto-oscillatory dynamics as a function of magnetic field magnitude and direction.