CALCULATED ELECTRONIC AND MAGNETIC-STRUCTURE OF THE NITRIDES NIFE3N AND PDFE3N

The electronic and magnetic structure of the antiperovskite-structure transition-metal nitrides NiFe3N and PdFe3N are calculated employing the augmented-spherical-wave method. From these calculations the binding character is found to be mainly covalent for the nitrogen-iron bonds and metallic between the iron and nickel atoms, as stated in the earlier literature. The magnetic structure exhibits itinerant moments for the iron atoms and more localized moments at the Ni(Pd) atoms. Effects of external pressure are studied by varying the lattice constant. Such calculations yield the pressure dependence of the magnetic moments and the hyperfine fields. The total energy is computed as a function of magnetic moment and volume, yielding total-energy surfaces, that provide the basis for a spin-fluctuation model at finite temperatures. The possibility of an Invar-like behavior is found.