Effect of Pt substitution on the magnetocrystalline anisotropy of Ni 2 MnGa: A competition between chemistry and elasticity

The magnetocrystalline anisotropy (MAE) of Ni 2-x Pt x MnGa(0 x 0.25) alloys are investigated using the singular point detection technique and density functional theory. A slight reduction in MAE as compared to that of Ni 2 MnGa is observed due to Pt substitution. The calculated MAE varies almost linearly with the orbital moment anisotropy. A competition between the elastic and the chemical contributions explains the observed trend of the MAE with increasing Pt content. The large MAE in combination with the previously reported increase of the martensitic transition temperature makes these alloys promising candidates for ferromagnetic shape memory applications near room temperature.