Phase formation and dielectric phase transition in Ba1-xCaxTi0.6Zr0.4O3 solid solutions

Perovskite types Ba1-xCaxTi0.6Zr0.4O3 (with x = 0.0-0.5) ceramics have been prepared through solid state reaction route. The room temperature XRD study suggests the compositions with x = 0.0 and x = 0.1 have single phase cubic symmetry. With further increase in Ca content, solid solution breaks and an orthorhombic CaTiO3 like phase is developed. The dielectric study on single phase compositions (x = 0.0 and 0.1) reveals that the materials are of relaxor type and undergo a diffuse type ferroelectric phase transition. In the Ca containing composition higher transition temperature is observed than the pure BaTi0.6Zr0.4O3 materials. In the paraelectric region (above T-c) lower diffusivity is observed in the Ca containing composition. The strength of relaxation is calculated and found to be more in Ca containing material than that of pure BaTi0.6Zr0.4O3 composition. (c) 2006 Published by Elsevier Ltd.