Correlation between crystallinity and magnetism in a series of laser-ablated anatase Ti1-xCoxO2 thin films

We report on ferromagnetic Co-doped TiO2 films grown by laser ablation on LaAlO3 and SrTiO3 substrates. Films on both types of substrate are highly crystallized, very well epitaxial, single-phased anatase and show ferromagnetism far beyond room temperature. Due to the smaller lattice mismatch in the case of LaAlO3 substrates, films on LaAlO3 substrates are more oriented than films on SrTiO3 substrates, and therefore have better quality with a larger saturation magnetic moment. Besides x-ray diffraction data, our magnetic force microscopy results also suggest that the ferromagnetism in Co-doped TiO2 films probably does not stem from either Co-enriched TiO2 clusters or Co segregations.