Authors: K. Srinivas, P. Venugopal Reddy
Affilation: Osmania University, India
Pages: 947 - 950
Keywords: diluted magnetic semiconductors, nano materials, optical band gap, ferromagnetism
With a view to understand the influence of nano size on various structural, electronic and magnetic properties of nanostructured Sn1-xCoxO2, systematic investigations have been carried out. After synthesizing the samples by sol-gel route, structural characterization was undertaken by XRD, TEM, FT-IR and Raman techniques. The samples are having the tetragonal rutile structure with single phase without any detectable impurity. The average particle sizes obtained from TEM are in the range of 18 - 48 nm. The reduction of intensities of Raman peaks, shift in their positions, their shape and size distribution are found to be influenced predominantly by the nano size of the materials. The optical band gap of the materials clearly indicates a red shift with increasing particle sizes. From XPS data, it has been observed that the oxidation state of Co is +2 and changes from low spin state to high spin state as the nano size of the materials increase. Further, the phonon confinement effect and electronic structure have been analyzed. The Magnetization studies clearly indicated the presence of room temperature ferromagnetism in these samples. Further, the analysis of the saturation magnetization, Coercive field clearly indicated that they critically depend on nano size of the materials.