Nanopillar ferromagnetic nanostructure as highly efficient spin injector into semiconductor

Abstract

We report the prediction of a high spin injection ratio γ into a semiconductor (SC) contact, by using a ferromagnetic (FM), small-sized, and cylindrical nanopillar as the spin injector (SI). The increase in spin scattering within the FM nanopillar injects spin current into the SC, effectually mitigates the blockage of SI due to conductance mismatch. To minimize the spreading resistance (SR) which arises due to areal discontinuity at FM-SC interface, a thin low resistance metal is inserted at the interface such that SR is contained within it. With the insertion, we obtained γ of as high as 40%, compared to just 3% without insertion, and an even lower value of 0.5% without the nanopillar patterning. © 2007 American Institute of Physics.