High temperature and pressure study on structural and thermophysical properties of Co2XAl (X = Zr, Nb, Hf) Heusler materials by density functional theory calculations

摘要

Heusler compounds exhibit a wide range of properties for both fundamental and potential technological interests. The extensive tunability of the Heusler compounds, through chemical substitutions and structural motifs, makes the family specifically interesting. As the maturity of these materials grows and commercial applications become more near-term, the properties of these materials become an important factor to both their processing and their final use. Here, we have investigated elasto-mechanical, transport and thermodynamics of Co2XAl (X = Zr, Nb, Hf) Heuslers. The exchange correlation potentials are figured out by GGA, GGA + U-eff and GGA + mBJ methods to obtain more precise results of these materials. The continuity in the P-V plot indicates the absence of any structural phase transition from highly symmetric cubic structure to other structural phase. The magnetic interactions were taken into consideration, among which ferromagnetic configuration was found to be stable. The calculated elastic parameters recommend that these alloys are mechanically stable and possess ductile character. The efficient transport parameters with half-metallic and ductile nature suggest the likelihood applications of these alloys to design hard spintronic devices or potential thermoelectric materials. Furthermore, the high temperature and pressure variation of thermodynamic properties were calculated using the quasi-harmonic Debye approximation to descript its stability.