Enhancement of Ferromagnetic Ordering Curie Temperature in N-Doped MgO under Hydrostatic Pressure

Abstract

We have explored the magnetic properties of Nitrogen doped cubic MgO using the full potential linearized augmented plane wave (FP-LAPW) method. The unit cell has 128 atoms, and two Nitrogen atoms are placed in the positions of oxygen sites. This corresponds to 3.125% doping concentration. Our calculations predict that the ferromagnetic state, with a magnetic moment of about 1.0 μB per Nitrogen-dopant, is more favorable in energy than the nonmagnetic state, and the ferromagnetic correlations are influenced by the impurity bound state. The magnetic moment mainly arises from p orbital of Nitrogen which substitutes the Oxygen atom, with a little contribution from the Oxygen atoms surrounding Nitrogen atom. The resulting band structure and densities of states agree well with the recent theoretical works. The ferromagnetic ordering temperatures obtained from DFT simulations have been given in detail. Our results show that the pressure enhances the temperature in MgO:N.

d° Ferromagnetism of Magnesium Oxide

“…Kuang et al also reported that these composite defects promote magnetism in the case of oxygen vacancies [84]. It is contemplated that local magnetic moment is induced by the composite defects around the oxygen vacancy, when the exchange splitting of the oxygen vacancy is enhanced either by the hybridization between the N-p and nearest neighbor O-p orbitals or by applying on-site Coulomb repulsion and exchange interaction [81][82][83].…”

“…Thus, the theoretical investigations were carried out in this direction to revive the role of oxygen vacancies [79][80][81][82][83].…”