A first-principles investigation on the effect of the divacancy defect on magnetic properties of Fe94V6 alloy

Abstract

The effect of the divacancy defect on magnetic properties of Fe94V6 alloys was investigated using the first-principles calculations based on density functional theory. The model of Fe28V2 super-lattice for a divacancy in Fe94V6 alloy was established, in comparison with the perfect Fe30V2 super-lattice. For the first time, the effect of the on-site Coulomb repulsion term was considered to correct the underestimation for the bandgap. The magnetism of the Fe, V atoms, and the super-lattice were analyzed by the electron hybridization of the atoms, and the interactions between V and four different neighboring Fe atoms were also investigated. The results show that both Fe28V2 and Fe30V2 super-lattices are ferromagnetic, which is determined mainly by the strong ferromagnetism of Fe 3d electrons, and the hybridizations between Fe 3d electrons and Fe 2p and V 3d electrons account for the weak anti-ferromagnetism. When the Fe divacancy exists, the average magnetic moments of the Fe28V2 super-lattice and Fe atoms inside increase, while that of V atoms decreases due to the change of the Fe-V charges. The variation of the magnetic moments of different neighboring Fe atoms with respect to V atoms depends on the charge transfer and the Fe-V interaction.