Structural and low temperature Raman scattering studies in SrTi1-xCoxO3 nanoparticles synthesized by sol-gel method

We investigate effects of Co dopant concentration on the structure and low temperature Raman scattering properties in SrTi1-x Co (x) O-3 (x = 0.00, 0.10, 0.20, 0.30) nanoparticles prepared by sol-gel method. The dopant induced changes are studied by XRD, and Raman scattering measurements. The results show an average particle size of about 20 nm depending on the Co content and the lattice parameters decrease as increasing the Co content. In the Raman spectra, a broad structure in the region 100-500 cm(-1) is almost absent and the peaks in the region 600-800 cm(-1) show different weights with respect to SrTiO3, relating to structural changes. The anomalous change in the area ratio of Raman peaks as function of temperature suggests a phase transition in our samples in the range of 110-130 K. These results indicate that the Co ion has replaced the site of Ti in unit cell. This novel route also demonstrates the advantage of synthesizing the compound with low annealing temperature.