Room Temperature Ferromagnetism In Co-Doped Ceo2 Films On Si(001)

We investigate the room temperature ferromagnetism of nanocrystalline Co-doped CeO2 films electrodeposited onto Si(001) substrates. The nanocrystalline CeO2 films, containing from 0.5 to 13.2 at. % Co, present oxygen-vacancy formation with a considerable inclusion of Co into the lattice without evidence of metallic Co clusters or secondary phase formation. We correlate the robust ferromagnetism of this multifunctional magnetic oxide integrated on Si with two exchange mechanisms mediated by intrinsic defect centers observed in the emerging ferromagnetic insulators.