We investigate effects of Co dopant concentration on the structure and low temperature Raman scattering properties in SrTi_1-x Co _x O₃ (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. © 2010 Springer Science+Business Media, LLC.

Van Minh N., Phuong D.T.T.

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Từ khóa : Annealing temperatures; Area ratios; Average particle size; Co content; Co-dopants; Investigate effects; Lattice parameters; Low temperatures; Novel route; Raman peak; Raman Scattering measurements; Raman spectra; Scattering property; Sol-gel method; Sol-gel methods; SrTiO; Structural change; Structure; Unit cells; XRD; Gels; Nanoparticles; Phase transitions; Raman scattering; Raman spectroscopy; Scattering; Sol-gels; Sols; Sol-gel process