Electronic structure and ferromagnetic effect in Ni2MnGa alloy

By using the first-principles discrete variational method (DVM), we have investigated the magnetic contribution to the binding energy, the Fermi energy level, the interatomic energy, the bond order (BO), the total density of states (DOS), and the charge density distribution for varying c/a in Ni2MnGa alloy. The binding energy curves for the ferromagnetic (FM) phase for varying c/a are more complicated than those in the nonferromagnetic (NM) phase whose energy difference displays the magnetic contribution to the binding of the crystal. The interactions between the central atom Mn and the surrounding atoms, including the interatomic energies and the BOs, are different from each other, which leads to crystal anisotropy. The finding suggests that the interatomic energy difference between the FM and NM phases will be the origin of magnetic anisotropy. The difference in electron density on the different distortions for the FM and NM phases varying with c/a shows the different redistribution of the magnetization for the Mn and Ni in the [110] plane.