Generation of open-circuit spin current on GHz scale in structured Pt/YIG by electric fields

Abstract

Recent studies point to virtual hopping of the oxygen atoms and strong spin-orbit interaction as the source of coupling of the magnetic order of yttrium iron garnet (YIG) to an applied external electric field. As shown here, an electric field can thus be utilized for pumping magnonic spin current at structured Pt / YIG interface. A finite uniform temperature is needed to thermally activate magnons as the carriers of the spin current. This current arises thus at finite uniform temperatures, applied external electric field, and for appropriate nanostructuring. Due to the inverse spin Hall effect, the generated magnonic spin pumping current is further converted into an electric voltage. We analyze the underlaying microscopic mechanism for the generation of the spin current and demonstrate by full numerical simulations that the spin current is substantial. Effects related to static as well as time-dependent E-fields and enhanced damping are discussed. The results indicate that generally, the proposed method for generating spin currents works for magnetic insulators that respond to a moderate electric field, and that the required nanostructuring poses no obstacle making this approach highly suitable for spintronic applications.