Electronic and Magnetic Properties of Ni_2–xPt_xMnGa Cubic Alloys

In this study, we have established a careful analysis on the effect of Pt substitution at Ni sites on the electronic structure and magnetic properties of the Ni₂MnGa system in both cubic and tetragonal phases using FP-LAPW+lo method based on density functional theory. Two Pt concentrations were investigated x = 0.125 and 0.250 in Ni_2–xPt_xMnGa Heusler alloys using the supercell model. GGA+U calculations show that Ni_2–xPt_xMnGa alloys (x = 0, 0.125, 0.250) are stable in the cubic structure and the lattice parameters increase linearly with increasing platinum concentration. Band structure calculations show overlapping bands at the Fermi level indicating that these alloys are metallic. The atomic and total magnetic moments increase with increasing Pt concentration, which is responsible to the strengthening of ferromagnetism in these alloys. The anisotropy energy calculations predict that [100] and [010] axis are the easy and hard one respectively in our cubic ferromagnetic Pt doped Heusler. Our Pt doped Ni₂MnGa alloys could be synthesized to obtained novel shape memory alloys.