Ab initio investigation of structural, magnetic, electronic, mechanical, and strain-dependent properties of full-Heusler compounds Ir2CrZ (Z = B, Al)

We report a first-principles investigation of the structural, magnetic, electronic, mechanical, and strain-dependent properties of full-Heusler compounds Ir2CrZ (Z = B, Al) within density functional theory using the generalized gradient approximation. Structural optimization and total energy calculations show that both alloys prefer the L21 structure Fm3̄m (No. 225) and are more stable in the ferromagnetic state than in the non-magnetic configuration. Spin-polarized band structures reveal that Ir2CrAl exhibits robust half-metallic behavior with a minority-spin indirect gap of 0.195 eV, while Ir2CrB shows nearly half-metallic character with a narrow gap of 0.027 eV. The density of states analysis indicates that Ir 5d and Cr 3d states dominate near the Fermi level, with Al substitution enhancing d–d hybridization and spin polarization. Magnetic moment calculations satisfy the Slater–Pauling rule, yielding an integer total moment of ∼3μB for both compounds, with Cr providing the dominant local contribution. Strain calculations in the range of −5% to +5% show that total magnetic moments remain nearly invariant, confirming magnetic robustness. Spin polarization remains high across the strain range, reaching nearly 100% in Ir2CrB under compression and ∼99.9% in Ir2CrAl, decreasing slightly under tensile strain due to strain-induced shifts in minority-spin states. Elastic constant analysis indicates that both alloys violate the Born stability criteria, suggesting mechanical instability in the ideal cubic phase. Overall, these results highlight the strong spintronic potential of Ir2CrAl and Ir2CrB, while motivating further work on structural stabilization and strain engineering.