Structure, electrical and dielectric properties of Ca substituted BaTiO3 ceramics

BaTi1-xCaxO3-x [BTC100x] ceramics were synthesized via solid-state reaction method. Effect of Ca substitution on the structure, electrical and dielectric properties of BTC100x ceramics was systematically investigated. Calcined BTC100x powders were in tetragonal phase when x ≤ 0.01, whereas transformed to cubic at x > 0.01. Additionally, the diffraction peak (200) shifted to lower angles with increasing x, indicating increased unit cell volume. Meanwhile, Ba0.97Ca0.03TiO3 [BC3T] ceramic was prepared and studied, to compare with BaTi0.97Ca0.03O2.97 (BTC3). It was found that pure BaTiO3 [BT] and BC3T ceramics had the similar structural and dielectric properties, whereas BTC3 ceramic showed much difference，XRD patterns, Raman spectrum, impedance spectra and dielectric-temperature spectra provided strong evidence of Ca2+ substitution at Ti site in BT lattice. Finally, BTC100x ceramics were produced and dielectric properties were investigated. With increasing x, the Curie temperature decreased from 128 °C (BT) to 42 °C (BTC5).