Inductive detection of fieldlike and dampinglike ac inverse spin-orbit torques in ferromagnet/normal-metal bilayers
Andy Berger, Eric R. Edwards, Hans T. Nembach, Justin M. Shaw, Alexy D. Karenowska, Mathias Weiler, Thomas J. Silva
Phenomena that result from strong spin-orbit coupling (SOC) at ferromagnet/normal metal (FM/NM) interfaces hold great promise for the development of efficient and scalable spintronic devices. SOC drives non-equilibrium spin-charge conversion, manifest as both current-driven spin torque [1,2] and spin precession-driven current [3-6]. SOC also underlies the interfacial Dzyaloshinskii-Moriya interaction (DMI) [7,8]. While efficient spin-charge conversion and large DMI often coincide, e.g. Refs. [9,10], a causal connection between these two phenomena has not yet been experimentally established. It was recently proposed that inter-facial DMI generates a Rashba-Edelstein effect (REE) , whereby charge current exerts a field-like torque at the FM/NM interface. The theory predicts a simple quantitative relation between the DMI and the REE. By use of a powerful new microwave spectroscopy method to detect inverse spin-charge conversion processes in FM/NM bi-layers, we demonstrate that the magnitude of the REE is in good agreement with the theoretically predicted value based on the previously measured value of DMI in identical bilayers .