First-principles calculation of the intersublattice exchange   interactions and Curie temperatures of full Heusler alloys Ni2MnX (X=Ga, In,   Sn, Sb)
  The interatomic exchange interactions and Curie temperatures in Ni-based full Heusler alloys Ni2MnX with X=Ga, In, Sn and Sb are studied within the framework of the density-functional theory. The calculation of the exchange parameters is based on the frozen-magnon approach. Despite closeness of the experimental Curie temperatures for all four systems their magnetism appeared to differ strongly. This difference involves both the Mn-Mn and Mn-Ni exchange interactions. The Curie temperatures, Tc, are calculated within the mean-field approximation by solving a matrix equation for a multi-sublattice system. Good agreement with experiment for all four systems is obtained. The role of different exchange interactions in the formation of Tc of the systems is discussed. 
E. Sasioglu, L. M. Sandratskii, and P. Bruno