MODELING THE MAGNETIC-PROPERTIES OF HEUSLER ALLOYS

The magnetic behaviour of the Heusler alloys is modeled by an fcc Heis enberg system. The Hamiltonian includes effective magnetic couplings b etween first, second and third neighbor pairs. The ground state phase diagrams at zero magnetic field and their range of stability with rega rd to the interaction parameters are obtained using the method of line ar inequalities. The Curie and Neel temperatures are calculated as a f unction of the interactions in the mean field approximation. The model is applied to describe the phase transitions occuring in the Pd2MnSbx In1-x alloys.