Structural, optical and electrical properties of barium titanate

Barium titanate is one of the most studied perovskite materials owing to its ability to the substitution in both sites, to its high dielectric constant and to its stability. It is characterized by a diversity of remarkable properties, especially ferroelectric and dielectric properties, which can be improved by doping, making this material suitable for many applications. We have investigated the effect of calcium ion substitution on the structural, optical, electrical and dielectric properties of this compound. Ba0.9Ca0.1TiO3 ceramic was elaborated using the solid-state diffusion method. This compound crystallized in the tetragonal phase with a crystallite size of 22 nm. Fourier transform infrared spectroscopy measurements revealed that octahedral vibrations are affected by Ca incorporation. Electrical analyses show that the compound has a semiconductor behavior, and that both grains and grain boundaries are responsible for the thermal evolution of the conduction mechanisms. Two different transition temperatures were detected. One of them coincides with the Curie temperature, which is confirmed by dielectric measurements. The compound shows a high dielectric constant up to 420 K which is seemingly constant in a wide frequency range. Such behavior is sought for the development of energy storage devices.