Half-metallic stability of the Heusler alloys TiZrIrZ (Z = Al, Ga, and In) under volumetric strain and tetragonal deformation

The study of the structural, mechanical, and magneto-elctronic properties of TiZrIrZ (Z = Al, Ga, In) quaternary Heusler alloys was performed using full-potential linearized augmented plane-wave (FP-LAPW) method, based on the density functional theory (DFT) with generalized gradient approximation (GGA). The findings show that the ferromagnetic phase of Type I atomic arrangement is energetically favorable. The calculated spin-polarized band structures of TiZrIrZ (Z = Al, Ga, and In) reveal that they are half-metallic materials, with indirect band gaps (half-metallic gaps) of 1.01(0.41 eV), 0.96(0.37 eV), and 0.91 (0.43 eV) in the minority spin channel, respectively. The ferromagnetism of TiZrIrZ alloys is caused by the d-orbitals of Ti and Zr atoms and the total magnetic moments verify the Slater–Pauling rule: $$M_{t} = Z_{t} - 18$$. The calculated Curie temperatures of TiZrIrZ (Z = Al, Ga, and In) are 545 K, 566 K, and 574 K, respectively. Moreover, the half-metallicity of all these alloys is kept by the volumetric strain and tetragonal deformation in the relatively large ranges, for the lattice parameter and c/a ratio, respectively.