Abstract
Pulsed laser deposited films of Co-doped anatase 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 sample, which exhibits a Curie temperature 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 high-temperature anneal during the first magnetization measurement, the very same sample shows a and almost full matrix incorporation of Co. This is close to that of as-grown 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 diluted magnetic semiconductor with of about 650–700 K.
- Received 3 December 2002
DOI:https://doi.org/10.1103/PhysRevB.67.115211
©2003 American Physical Society