Pulsed laser deposited films of Co-doped anatase TiO2 are examined for Co substitutionality, ferromagnetism, transport, magnetotransport, and optical properties. Our results show limited solubility (up to ∼2%) of Co in the as-grown films and formation of Co clusters thereafter. For the Ti0.93Co0.07O2-δ sample, which exhibits a Curie temperature (TC) over 1180 K, we find the presence of 20-50 nm Co clusters as well as a small concentration of CO incorporated into the remaining matrix. After being subjected to the hightemperature anneal during the first magnetization measurement, the very same sample shows a TC650 K and almost full matrix incorporation of Co. This TC is close to that of as-grown Ti0.99Co0.01O2-δ sample (∼700 K). The transport, magnetotransport, and optical studies also reveal interesting effects of the matrix incorporation of Co. These results are indicative of an intrinsic Ti1-xCoxO2-δ diluted magnetic semiconductor with TC of about 650-700 K.
|Original language||English (US)|
|Number of pages||6|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Mar 2003|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics