Ab Initio Investigations of the Structural, Electronic, Magnetic, and Thermal Properties of Cr2TaGe1-xSnx Quaternary Heusler Alloys

The first-principle calculations were performed in the framework of the density functional theory (DFT) using FP-LAPW method as implemented in Wien2k code to determine the structural stability, electronic, and magnetic properties of quaternary Heusler alloys Cr2TaGe1-xSnx (x = 0, 0.25, 0.50, 0.75, 1.00), The results showed that for the compounds, the AlCu(2)Mnl-type structure is energetically more stable than CuHg2Ti-type structure at the equilibrium volume. The calculated lattice constants for Cr2TaGe and Cr2TaSn are 6.081 angstrom and 6.311 angstrom, respectively. For mechanical properties, shear modulus, Young's modulus, elastic constants, Poisson's ratio and shear anisotropy factor have studied. Their obtained values reveal that these compounds are mechanically stable. The electronic band structures and density of states of our compounds show a half metallic character with total magnetic moments, - 3.00 mu(B) per formula unit with indirect band gap, 0.569 eV and 0.482 eV for Cr2TaGe and Cr2TaSn respectively. Regarding thermal properties such as the thermal expansion coefficient, heat capacity, and Debye temperature, we have applied a very suitable model for studying thermodynamics quantities called the quasi-harmonic Debye model. On the basis of these results, these alloys are predicted to be good candidates for future spintronic applications.