Effect of halogens in MgO to predict half-metallic ferromagnetism: By first principles calculations

Using the First Principles calculations within the frame work of density functional theory (DFT) the structural, electronic and magnetic properties were determined. Co-doping of halogen atoms in the host MgO with 12.5% concentration was performed and the half-metallicity property was investigated. It is very interesting that codoping of halogen atoms in the host MgO plays a vital role in exhibiting the half-metallic nature of the super cells Cl0.125Mg0.875Br0.125O0.875, Cl0.125Mg0.875I0.125O0.875 and Br0.125Mg0.875I0.125O0.875. Energy band gaps were found in spin up (majority) direction at the Fermi level which reveals the half-metallicity of the compounds. Super cells were found stable in the ferromagnetic phase as compared to the non-magnetic phase. Lattice constants and equilibrium energies were calculated after volume optimization was carried out. In super cells, the halogen atoms which replace the Mg atoms contributes in producing magnetic moment but which replace O atoms having a negative impact on a total spin magnetic moment. Moreover, the contribution to create a total spin magnetic moment in the super cells is due to Mg atoms and O atoms.