Effect of Ni-substitution on Ni2MnGe Heusler alloys: Ab initio study

The effect of Ni-substitution on magnetic properties of Ni2MnGe alloy has been investigated by first principles method FPLO, which is used in the CPA form. The theoretical lattice parameters obtained from the dependence of the total energy on the lattice parameter are comparable with experimental ones. A decreasing trend of total magnetic moment with Ni-substitution is found for Ni2+xMn1−xGe for studied concentrations of x. The linear pressure-magnetization behaviour is obtained for Ni2+xMn1−xGe for applied pressure from 0 to 9 GPa, and the pressure derivative of the total magnetic moment is calculated. The value of equilibrium bulk modulus of Ni2+xMn1−xGe (for x = 0.1 – 0.9) obtained from Murnaghan equation of state (EOS) shows that the studied compounds are less compressible than Ni2MnGe.