Study of diffuse phase transition in BaTiO3–LaAlO3

BaTiO3–LaAlO3 systems of the type Ba1−3xLa2xTi1−3xAl4xO3 and Ba1−xLaxTi1−xAlxO3 have been investigated. The compositions in each of the systems have been prepared by solid-state reaction. The presence of a perovskite single phase is confirmed using X-ray diffraction (XRD). XRD data has been analyzed using FULLPROF, a Rietveld refinement package and lattice parameters have been extracted. The microstructure of sintered pellets has been investigated using SEM. The compositions have been characterized by dielectric spectroscopy between room temperature and 250 °C. The resulting compounds exhibit a significant enhancement of the dielectric constant and diffuseness. The compositions with higher diffuseness have been characterized using high-temperature XRD to study the nature of the phase transition. On the basis of the high-temperature XRD data, core-shell structure is ruled out.