Effect of cobalt doping concentration on the structural and magnetic properties of Fe3O4

In this work, we investigate the effects of cobalt doping on the structural, magnetic and transport properties of half metallic Fe3O4 films fabricated on MgO (100) substrates by co-sputtering. The doped films exhibit a highly broadened metal–insulator Verwey transition as compared to that of undoped Fe3O4 films. The magnetic and transport properties of the doped films are markedly sensitive to the Co doping concentration; films with high Co doping exhibit almost negligible coercivity at room temperature. Magnetoresistance (MR) curves show linear magnetic field dependence for the undoped films, while a reduction in MR and departure from linear field dependence is observed for Co-doped films.