Electrostrictive Properties of Pr-Doped BaTiO3–CaTiO3 Ceramics

Pr-doped (1- x )BaTiO 3 – x CaTiO 3 ( x =0.20–1.0) ceramics were prepared by a solid-state reaction technique. Their structures were found to be a pure tetragonal phase for x ≤0.23, coexisting tetragonal and orthorhombic phases for x =0.25 to 0.90, and a pure orthorhombic phase for x ≥0.90, respectively. A large electrostrictive strain of 0.265%, 1.76 times that of BaTiO 3 ceramics, was obtained near the solubility limit on the side of the composite ( x =0.25), which is a diphasic ceramic composed of a ferroelectric tetragonal Ba 0.77 Ca 0.23 TiO 3 :Pr solid solution and a normal dielectric orthorhombic Ba 0.1 Ca 0.9 TiO 3 :Pr solid solution. The enhancement of electrostriction resulted from the doping effect and coupling of the large ionic polarization in Ba 0.1 Ca 0.9 TiO 3 :Pr with the non-180° domains in Ba 0.77 Ca 0.23 TiO 3 :Pr during the external electric field exertion.