Investigation of Ba1-xSrxTiO3 ceramics prepared from powders synthesized by the modified Pechini route

Ba1-xSrxTiO3 (x = 0, 0.20, 0.25, 0.30 and 0.35) nanopowders were prepared by Pechini method from titanium isopropoxide, barium and strontium carbonates using citric acid as a chelating agent and ethylene glycol as an esterification agent. X-ray diffraction data show the formation of (Ba,Sr)TiO3 solid solutions, free from secondary phases as BaCO3 or Ti-rich oxides, when the polymeric precursors were calcined in air at 850 °C for 2 h. Ceramic pellets with relative density of 85-93% were obtained after sintering at 1350 °C for 3 h. High values of the dielectric constants (of ~1500-12,000), low losses at the room temperature and a shift of the ferro-para phase transition temperature in the range of 7-127 °C with x decreasing were found. Lower values of the Curie constant for higher x indicate the increase of the chemical and electrical local heterogeneity degree.