The special features of ferromagnetism in ordered Heusler alloys

The electronic structure and magnetic properties of the Cu₂MnA, Ni₂MnA, Pd₂MnA, Co₂MnA, and Fe₂FeA compounds with cubic lattices, where A is a nontransition element anion (A=Al, In, Ge, As, Sn, Si, or Sb), are studied. An analysis is performed in terms of the generalized Hubbard model with an infinite electronic repulsion energy within the same atom. Equations for determining the spin magnetic susceptibility of the compounds are obtained. These equations are used to determine the conditions of ferromagnetic instability and to construct the phase diagram for the existence of ferromagnetic ordering.