First principle calculation on electronic and magnetic properties of new half-metal TiFe2O4

The new half-metal TiFe2O4 is designed and optimized based on first-principle pseudo-potentials. The electronic and magnetic properties including the spin-polarized energy band structures and state densities, the charges, and the molecular magnetic moments of TiFe2O4 are calculated and compared with those of Fe3O4. It is found that TiFe2O4 is a new ferromagnetic II-B half-metal, which is different from ferrimagnetic Fe3O4. The conductivity of TiFe2O4 is a little higher than that of TiFe2O4. The molecular magnetic moment of 6.68 mu(B) of TiFe2O4 is remarkably higher than 4.0 mu(B) of Fe3O4. Doping of Ti-atoms into Fe3O4 is helpful in improving the room temperature magnetoresistance. Localization of Fe 3d or Ti 3d electrons caused by hybridization of O 2p and Fe 3d or Ti 3d orbits is the mechanism by which TiFe2O4 has higher molecular magnetic moment and conductivity, and hence higher room magnetoresistance.