Magnetization and Spin Polarization of Heusler Alloys Co $_{2}$TiSn and Co$_{2}$ TiGa$_{0.5}$Sn $_{0.5}$

Abstract

The substitution effect on half-metallicity for Co-based Heusler alloys Co 2 TiGa 1-x Sn x was investigated by experimental measurements and first-principles band calculations. The synthesized alloys crystalized in the ordered L2 1 crystal structure. The spontaneous magnetization obeyed the Slater-Pauling rule, indicating the possibility that Co 2 TiSn and Co 2 TiGa 0.5 Sn 0.5 are half-metals. The first-principles band calculations revealed that Co 2 TiSn is half-metal and Co 2 TiGa 0.5 Sn 0.5 is nearly half-metal. The spin polarization P was determined by the Andreev reflection technique. The intrinsic P values were 58.9% for Co 2 TiSn and 58.2% for Co 2 TiGa 0.5 Sn 0.5 , respectively. The P values of Co 2 TiGa 1-x Sn x were relatively higher than other Co-based Heusler alloys. Thus, Co-based Heusler alloys Co 2 TiGa 1-x Sn x are possible candidates for half-metallic electrode materials in spintronic devices.