Electronic and magnetic properties of AlFe3 and AlFe3N nitride

Self-consistent band structure calculations were performed for the metal aluminide AlFe3 (in the fcc structure) and the nitride AlFe3N (perovskite-like nitride) at several lattice parameters in order to obtain the electronic structure and magnetic properties of these compounds. In this study we have employed the full potential linear augmented plane wave (FPLAPW) and the linear muffin-tin orbital (LMTO-ASA) methods. Our results show that the modeled AlFe3 is ferromagnetic (FM) with 2.07 mu(B) as the magnetic moment at Fe sites. On the other hand, AlFe3N is non-magnetic (NM) contrary to other perovskite nitrides that show magnetic order. Hence as the stable phase of AlFe3 is magnetic with DO3 structure a crystallographic transformation occurs accompanied by a magnetic transition from a non-magnetic perovskite structure to a magnetic DO3 structure as AlFe3N lose nitrogen atoms. The LMTO and FPLAPW total energy calculations give the equilibrium volume for both compounds. For AlFe3N, the FPLAPW calculations give the equilibrium volume that agrees well with the experimental lattice spacing, which is not achieved by LMTO calculations within the same accuracy. The calculated magnetic moment as function of the lattice parameter for the AlFe3 shows a collapse of the magnetism at certain critical lattice parameter whose FPLAPW value (2.962 Angstrom) differs only slightly from the LMTO value (3.041 Angstrom). (C) 2004 Elsevier B.V. All rights reserved.