Properties of Ba_1−xSr_xTiO₃ Ceramics Prepared by the Modified-Pechini Method

Abstract

Single phase Ba _1−x Sr _x TiO ₃ powders (x = 0; 0.20; 0.25; 0.30 and 0.35) were obtained via modified Pechini method after annealing of the polymeric precursors in air at 850°C for 2 hours. When the strontium content, x, increases, the tetragonality degree decreases, so that the unit cell symmetry changes from a tetragonal one, specific to the pure BaTiO ₃ powder towards a cubic form, for powders with x ≥ 0.30. Dense and homogeneous microstructures, free of secondary phases were obtained for the related ceramics resulted after sintering in air, at 1350°C for 3 hours. High values of the relative permittivity (of ∼ 1500–12000) and low dielectric losses were obtained at the room temperature for all the compositions.

Keywords:

• BaTiO₃
• organic precursors
• dielectric properties
• ferroelectric properties
• perovskite

Acknowledgments

This work was supported by the Romanian grant CEEX – FEROCER (2006–2008).