Luana Emiliana Iorio

Effect of nitrogen on the magnetic moment of α-Fe and FeCo alloys from first-principle calculations

The effect of nitrogen on the magnetization of α-Fe and Fe1−xCox alloys was studied within the spin-polarized density functional theory. For α-Fe, the average magnetic moment (per atom) μ increases with increasing concentration of interstitial nitrogen. The increase in moment occurs due to inter-atomic charge transfer, which increases the moment on the Fe atoms that are next-nearest neighbor to the N atom. In Fe1−xCox alloys, nitrogen suppresses the peak in μ(x) and shifts it to lower Co concentrations compared to the pure Fe-Co system. The decrease in moment in the FeCo-N system occurs due to competing inter-atomic (promoted by N) and intra-atomic (promoted by Co) charge transfer on the Fe atoms surrounding the N atom. The addition of nitrogen was not found to significantly increase the magnetization of α-Fe and Fe1−xCox alloys.