Dielectric properties of substituted BaTiO3 synthesized by the coprecipitation method

Abstract

Various substituted BaTiO₃ materials were synthesized using the co-precipitation method. BaCO₃ powders as well as carbonate powders of Sr, Ca, Bi, and nitrate powders of Pb were used to synthesize various monosubstituted BaTiO₃ materials of composition Ba_1-xR_xTiO₃ (where R = Bi, Sr, Ca, Pb and x = 0.25, 0.50, 0.75, 1.0). Appropriate amounts of the Ba and substituent precursors were mixed in nitric acid. TiCl₄, was then added to the mixture. Coprecipitation was achieved by slowly adding ammonium hydroxide while continuously stirring the mixture. The precipitates were washed, dried, and then calcined at 700°C for 8 hrs. The resulting powder was then formed into pellets and sintered at 1000°C for 12 hrs. A total of 16 samples were made. Characterization tests used were scanning electron microscopy, capacitance measurements using a bridge circuit, resistivity measurements, and x-ray diffraction. The dielectric constant and dielectric loss were calculated from the capacitance data.