Efficient Spin Detection Across the Hybrid Co/GaAs Schottky Interface

The electron spin detection efficiency was studied across Co/GaAs structures using photoexcitation techniques. Two sets of samples were prepared where the substrate surface was pretreated by annealing prior to growth for the first set whereas for the second no annealing treatment was carried out. While, in the annealed sample, spin detection was observed, the nonannealed case showed no spin-dependent transport effects. This is attributed to the absence of a Schottky tunnel barrier to facilitate tunnelling through the interface, as the transport mechanism responsible for the spin filtering. Furthermore, it illustrates the influence of the interface quality on spin dependent transport processes for the general case of any FM electrode