Structural, elastic, magnetic and electronic properties of Ti-based Heusler alloys

The structural, elastic, magnetic and electronic properties of titanium-based alloys Ti2XIn (X = Fe, Co and Ni) are investigated by the first-principles calculations based on density functional theory using the Vienna ab-initio simulation code. The lattice constants of Ti2XIn (X = Fe, Co and Ni) alloys are optimized for the two possible structures such as Cu2MnAl and Hg2CuTi. It is found that at ambient pressure Ti2XIn (X = Fe, Co and Ni) alloys are stable in Hg2CuTi-type crystal structure. The total magnetic moments (M-t) and the energy gap (E-g) of Ti2XIn (X = Fe, Co and Ni) alloys are calculated for various pressures. The total magnetic moments of Ti2XIn (X = Fe, Co and Ni) alloys in Hg2CuTi structure follow the rule mu(t) = Z(t) - 18 and agree with the Slater-Pauling (SP) curve quite well. In both structures (Cu2MnAl and Hg2CuTi), the calculated magnetic moment of Ti2XIn (X = Fe, Co and Ni) alloys decreases with increase in pressure. Density of states shows the metallic nature of Ti2XIn (X = Fe, Co and Ni) alloys in Cu2MnAl structure and half-metallic (HM) behavior in Hg2CuTi structure, i.e., majority spin channel is strongly metallic and the minority spin maintains the gap at the Fermi level at the equilibrium lattice constant.