Dielectric characteristics and their field dependence of (Ba, Ca)TiO3 ceramics

(Ba1−xCax)TiO3 ferroelectric ceramics were prepared by a solid state reaction method, and their dielectric properties and the field dependence of dielectric constant were characterized together with the microstructures. The BaTiO3-based solid solution with tetragonal structure was obtained for x=0.1, and a tetragonal to cubic phase transition was observed with increasing x since the CaTiO3-based solid solution phase with cubic structure appeared for x=0.3 and became the major phase for x=0.7. The dielectric constant decreased with increasing x, while the dielectric loss and temperature dependence were significantly suppressed. The obvious field dependence of dielectric constant was obtained for the compositions with x<0.5, and it became weaker with increasing x.