Halfmetallicity, mechanical and thermodynamic study on iridium based compounds by First Principles calculations

Abstract

Using First Principles calculations as implemented in Wien2K, Electronic structure, Magnetic, Half-Metallic, Mechanical and thermodynamic properties has been studied for Ir2MnAl and Ir2MnGa full Heusler alloys. Structural optimization was performed for nonmagnetic (NM), Ferromagnetic (FM) and antiferromagnetic (AFM) states using LSDA as exchange-correlation potential. Both the alloys were found to be stable in FM states. These alloys have satisfied Born mechanical stability criteria in ferromagnetic L21 structure. Elastic constants, Mechanical properties, and thermodynamic properties were calculated. They reveal that these alloys being incompressible, ductile and anisotropic. Ir2MnAl exhibited half metallicity with 100% spin polarization, while, Ir2MnGa was observed to be metallic with 96% spin polarization. The total spin magnetic moment per unit cell of both the alloys satisfy Slater-Pauling rule with 4 μB and 4.02 μB for Ir2MnAl and Ir2MnGa respectively. Ir2MnAl was observed to be a half-metallic ferromagnet with an indirect energy gap of 0.25eV. Curie temperature was calculated using the mean field approximation method to be 110K for Ir2MnAl. Since the calculated value of Curie temperature is low, Ir2MnAl, would not be suitable for room temperature spintronic devices.