We investigate effects of Fe dopant concentration on the structure, as well as low temperature Raman scattering and electrical transport properties in SrTi_1-x Fe_xO₃ (x = 0.00, 0.10, 0.20, 0.30, 0.40) nanoparticles prepared by sol-gel method. The results show an average particle size of powder is about 30 nm, and the lattice parameters decrease as increasing the Fe content. In the Raman spectra, a broad structure in the region 200-500 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 with increasing dopant concentration in conjunction with increasing grain boundary contribution to the impedance. The abrupt change in Raman peak position as function of temperature suggests a phase transition in our samples in the range of 110-150 K. These results indicate that the Fe ion has replaced the site of Ti in unit cell. These results also demonstrate the feasibility of synthesizing the compound with low annealing temperature. © Springer Science+Business Media, LLC 2010.

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

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Từ khóa : Abrupt change; Annealing temperatures; Average particle size; Dopant concentrations; Dopant effects; Electrical transport properties; Fe content; Investigate effects; Lattice parameters; Low temperatures; Raman peak; Raman spectra; Sol-gel methods; SrTiO; Structural change; Structure; Unit cells; Electric properties; Gels; Grain boundaries; Nanoparticles; Phase transitions; Raman spectroscopy; Semiconductor doping; Sol-gel process; Sol-gels; Sols; Transport properties; Raman scattering