The effect of temperature on electronic, elastic and thermodynamic properties of Co2MnX (X = Si and Ge)

We investigated the effect of temperature on the electronic, elastic, and thermodynamic properties of Co-based full-Heusler Co2MnSi and Co2MnGe. The results show that the alloys are half-metallic ferromagnetic. The spin polarization is 97.90% for Co2MnSi, while for Co2MnGe is more than 85.3% below 1000K. The study of elastic constants and their associated parameters predicted that the two alloys are mechanically stable in the temperature range of 0-1000 K. Both alloys are ductile, anisotropic, and characterized by ionic bonds. In addition, Co2MnGe is less hard than Co2MnSi, but the latter is more sensitive to temperature variations than Co2MnGe. The electronic and vibrational contributions to the thermodynamic properties were computed separately in the temperature range of 0 K to 1000 K. The high spin polarization and mechanical stability make these alloys more appropriate for spintronic applications.