Nitriding effect on structural stability and magnetic properties of FeAl alloys: DFT study

Using the DFT calculations, the phase stability, structural deformation and magnetic moment of Fe-riche FeAl alloys in presence of different percents of nitrogen were calculated. The formation enthalpy of these Fe-Al alloys indicates that N preferred the octahedral site than the substitution one. Significant changes occur in this energy, affected by N and Fe content causing local distortions. From 25 at% N, the phenomenon of saturation appeared and the substitution takes place. The addition of 6 at% N stabilizes Fe9Al7 and Fe10Al6. The presence of N atom leading to decrease the total magnetic moment of FeAl nitride when the magnetic order is antiferromagnetic between N and Fe atom. This magnetic moment increased by the ferromagnetic coupling between Fe and N, thus increasing the Fe local magnetic moment and the magneto-volume effect.