LAUSR

A highly spin-polarized electron beam is extracted via field emission from a ⟨100⟩-oriented Heusler alloy Co2MnGa emitter, which is fabricated through ion milling of a crystallized thin film and well characterized through H2-promoted field evaporation and field ion microscopy (FIM). Crystalline facets of low-index planes such as the (100) and {011} planes can be observed as ring structures in the H2-Ne FIM images, despite the ternary nature of the alloy. The well-defined (100) surface at the emitter apex is the emission site, having higher emission current than other locations. The maximum spin polarization of the field-emitted electrons from the Co2MnGa(100) surface is 61%–76% and can be observed under a 1-nA probe current at 44 K. Although decreased spin polarization is observed with elapsed time, cleaning performed by the field evaporation process restores the spin polarization to the initial value. The spin polarization of more than 60% obtained even at room temperature surpasses those previously reported for transition metals such as Fe, Co, and Cr on W tips.A highly spin-polarized electron beam is extracted via field emission from a ⟨100⟩-oriented Heusler alloy Co2MnGa emitter, which is fabricated through ion milling of a crystallized thin film and well characterized through H2-promoted field evaporation and field ion microscopy (FIM). Crystalline facets of low-index planes such as the (100) and {011} planes can be observed as ring structures in the H2-Ne FIM images, despite the ternary nature of the alloy. The well-defined (100) surface at the emitter apex is the emission site, having higher emission current than other locations. The maximum spin polarization of the field-emitted electrons from the Co2MnGa(100) surface is 61%–76% and can be observed under a 1-nA probe current at 44 K. Although decreased spin polarization is observed with elapsed time, cleaning performed by the field evaporation process restores the spin polarization to the initial value. The spin polarization of more than 60% obtained even at room temperature surpasses those previously repo...