Interface-driven spin-torque ferromagnetic resonance by Rashba coupling at the interface between non-magnetic materials

摘要

The Rashba-Edelstein effect stems from the interaction between the electron'sspin and its momentum induced by spin-orbit interaction at an interface or asurface. It was shown that the inverse Rashba-Edelstein effect can be used toconvert a spin- into a charge current. Here, we demonstrate that a Bi/Ag Rashbainterface can even drive an adjacent ferromagnet to resonance. We employ aspin-torque ferromagnetic resonance excitation/detection scheme which wasdeveloped originally for a bulk spin-orbital effect, the spin Hall effect. Inour experiment, the direct Rashba-Edelstein effect generates an oscillatingspin current from an alternating charge current driving the magnetizationprecession in a neighboring permalloy (Py, Ni80Fe20) layer. Electricaldetection of the magnetization dynamics is achieved by a rectificationmechanism of the time dependent multilayer resistance arising from theanisotropic magnetoresistance.