Cobalt-Doped Anatase TiO2: A Room Temperature Dilute Magnetic Dielectric Material

We experimentally investigate the room temperature ferromagnetism observed in insulating Co doped anatase TiO 2 thin films grown by sputter deposition. The Co was uniformly incorporated in the lattice as Co(II) with no evidence of Co metal. A series of annealing treatments were carried out to optimize the ferromagnetic ordering and a saturation moment of 1.1 μ B /Co atom at 300 K was obtained with UHV annealing at 450°C. Both as-deposited and annealed films were highly insulating at room temperature. Results show that the ferromagnetism is strongly dependent on the number and distribution of oxygen vacancies in the Co:TiO 2 lattice.