Effect of ionic radii on the Curie temperature in Ba1-x-ySrxCayTiO3 compounds

A series of Ba1-x-ySrxCayTiO3 compounds were prepared with varying average ionic radii and cation disorder on A-site. All samples showed typical ferroelectric behavior. A simple empirical equation correlated Curie temperature, T-CI, with the values of ionic radii of A-site cations. This correlation was related to the distortion of TiO6 octahedra observed during neutron diffraction studies. The equation was used for the selection of compounds with predetermined values of T-C. The effects of A-site ionic radii on the temperatures of phase transitions in Ba1-x-ySrxCayTiO3 were discussed.