Resistively detected microwave absorption by planar spin oscillators

Abstract

We report on a novel class of RF spintronics devices directed towards making nanoscale microwave sources. Microwave emission is produced by a process of spin resonance that occurs in hybrid semiconductor-ferromagnetic nanostructures when a two-dimensional electron gas is subjected to both a magnetic field gradient and a constant magnetic field applied at right angles of each other. Current injection activates electron spin oscillations in the magnetic field gradient, whilst conversely, driving the spin dynamics with a microwave field modifies the channelling resistance perpendicular to the magnetic field gradient. We have irradiated GaAs/AlGaAs/Dy nanowires and observed resistance peaks induced by the microwave field. We have analyzed their dependence in the 50-110GHz and the 6T-15T range to extract relevant spin parameters. The absorption of microwave by spin oscillators is compared to the ferromagnetic resonance of Dysprosium.