Étude ab-initio de la structure électronique et magnétique des composés à base d’azote

Abstract

In the framework of density functional theory (DFT), spin-polarization and pressure effects on the structural, magnetic and electronic properties of the 3d transition-metal mono- and semi-borides TM-B and TM2B (TM=Mn, Fe, Co), respectively, have been studied using the full-potential Linearized augmented plane-wave method (FP-LAPW) with both local density approximation (LDA) and generalized gradient approximation (GGA). We have studied also the structural, magnetic and electronic properties of the transition metal mono-nitrides TMN (TM=Mn, Fe, and Co). We have showed the effects of electron correlation on the structural, magnetic and electronic properties for both RS-FeN and ZB-FeN phases using GGA +U. The calculated lattice constants, bulk modulus, pressure derivative and magnetic moment for all the compounds studied were found to be in very good agreement with other works. It has been found that the spin polarization and pressure have a significant impact on the cell volume, bulk modulus and magnetic moment for MnB, FeB, Fe2B and Co2B ferromagnetic compounds. Finally, we remarked that the electron correlation plays crucially important role in determining the structural and magnetic stability and different properties for FeN compound.