Half-metallicity in europium oxide conductively matched with silicon

EuO1-x-a remarkably versatile ferromagnetic semiconductor with variable transport properties incorporated into a heterostructure with n+ doped silicon is shown to be similar to 90% spin polarized by Andreev reflection (AR) spin spectroscopy. The AR measurements were done in a planar geometry with an InSn superconducting film. A simple reactive growth technique was used to controllably introduce oxygen vacancies into EuO1-x to adjust its carrier concentration. We demonstrate by direct measurements of spin polarization that half-metallicity of EuO1-x can be achieved in the films conductively matched with Si, thus making EuO1-x one of the most attractive materials for silicon-based spintronics.