Spin polarization of field‐emitted electrons from ferromagnetic half‐metallic Heusler alloy Co₂MnSi

Abstract

To develop a spin-polarized field emitter with high brightness available at room temperature, spin polarization of Heusler alloy Co 2 MnSi thin film deposited onto a chromium buffer layer on a polycrystalline tungsten needle tip surface was measured with Mott polarization analyzer. Typical electron emission pattern of Co 2 MnSi thin film displayed a mosaic pattern, which consisted of small bright spots, and the substrate plane of the brightest spot was a W(001) facet. Polarization direction obtained from the brightest spot was <110> direction of substrate tungsten which corresponded to a magnetic easy axis of Co 2 MnSi, if the film grew epitaxially on the W(001) plane via the chromium buffer layer. About 30% of spin polarization was obtained from Co 2 MnSi film annealed at 600 K for 2 h.

Fabrication of a Spin-Polarized Electron Source with a Single Magnetite Whisker

“…The spin polarization of field-emitted electrons was evaluated by a Mott electron polarimeter equipped with a field electron microscope (FEM). 5) Before the measurements, the sample was annealed at 1200 K for 390 s to remove contaminations from the surface and its condition was checked by an FEM image. The measurement was performed at room temperature under no magnetic field.…”