Magnetization and spin polarization of Co2−xFexMnSi Heusler alloys

We report magnetization and spin polarization of Co2-xFexMnSi Heusler alloys. Co2-xFexMnSi Heusler alloys are theoretically predicted to be half-metals (HM's) and generally possess high Curie temperature. The fact that the saturation magnetization of Co2-xFexMnSi for 0 ≤ x ≤ 1.5 obeys the Slater-Pauling rule reveals that those compounds are experimentally expected to be HM's. Therefore, the spin polarization of Co2-xFexMnSi Heusler alloys was determined by the Andreev reflection technique using Co2-xFexMnSi/Pb planar-type junctions. The obtained differential conductance was able to be fitted very well by the modified Blonder-Tinkham-Klapwijk theory. From analysis of spin polarization measurements, we have found the spin polarization of P = 0.50 for x = 0.5 and P = 0.52 for x = 1.25, respectively. Consequently, the spin polarization was less dependent of different concentrations of x.