Electronic, structural, magnetic and thermodynamic properties of the half-metallic ferromagnetic compounds containing chrome and tantalum Cr₂TaZ (Z = Al, Ga and Sb)

A theoretical study of magnetic, electronic structure, mechanical and thermodynamic properties of Cr₂TaZ (Z = Al, Ga and Sb) Heusler alloys has been extensively investigated by the full-potential linearized augmented plane wave (FP-LAPW) method with the Generalized Gradient Approximation (GGA). Structural parameters such as lattice constant \((a)\) $(a)$ , bulk modulus \((B)\) $(B)$ and first pressure derivative of bulk modulus \(({B}^{,})\) $(B^{,})$ were obtained by using the Murnaghan equation. The calculated lattice constants for Cr₂TaAl, Cr₂TaGa and Cr₂TaSb alloys are for 61,029, 61,170 and 60,795 Å, respectively. It is found that the L2₁-type (AlCu₂Mnl-type) structure is energetically more stable than the X-type (CuHg₂Ti-type) structure due to the lower total energy. The results of elastic constants robustness show that the mechanical stability of Cr₂TaZ (Z = Al, Ga and Sb) can be well-maintained. The calculated electronic band structure reveals the metallic nature of Cr₂TaZ (Z = Al, Ga and Sb) and its total magnetic moment of 2.00 \({\mu }_{B}\) ${\mu }_B$ is mainly contributed by Cr atom from strong spin splitting effect, as indicated with the distinctive distributions of the density of states in two spin directions. Furthermore temperature and pressure dependence of thermodynamic properties of these materials have been examined in the ranges (0–1400 K) and (0–25 GPa), respectively.