Enhanced Spin Polarization of Co₂MnGe Heusler Alloy by Substitution of Ga for Ge

Abstract

Point contact Andreev reflection (PCAR) measurements indicated that the conductive spin polarization of the Co2MnGe Heusler alloy was enhanced substantially by the substitution of Ga for Ge. While the spin polarization of the conductive electrons of Co2MnGe and Co2MnGa was estimated to be around 0.6, that of the Co2MnGe0.75Ga0.25 quaternary alloy was 0.74, the highest value measured by PCAR for Heusler alloys. Moreover, the alloy was found to be an L21 intermetallic compound having a high Curie temperature of 895 K.