Spin polarization of field-emitted electrons from half-metallic Co2MnSi thin films grown on a W(001) facet.

We measured spin polarization of electrons field-emitted from half-metallic Co(2)MnSi thin film grown on a W(001) facet via chromium buffer layer using Mott scattering. For spontaneously magnetized samples, values of polarization at room temperature were observed in a range from 10% to 46% and the polarization direction was 110 orientation of substrate tungsten, which agreed with an easy axis of magnetization of bulky Co(2)MnSi. An enhancement of polarization was observed as a consequence of applying a magnetic field of 350G perpendicular to the emitter axis after the annealing at 800K. This result is considered to be caused by improvement in crystallinity of the evaporated film due to annealing.