In-situ diffuse phase transition at the Curie point of BaTiO3 induced by amphoteric Ce3+/Ce4+ ions

Nominal (Ba1−xCex)(Ti0.95−x/4Ce0.05)O3 ceramics were prepared by a solid state reaction method. A complete solid solution called BC3TC5 was formed only at x=0.03, with a single-phase perovskite structure. The structural and dielectric properties of BC3TC5 were investigated by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, electron paramagnetic resonance, and dielectric measurements. BC3TC5 exhibited a cubic structure and a non-uniform microstructure. Ti-vacancy defects exist in BC3TC5, which has a feature of mixed valence of Ba-site Ce3+ and Ti-site Ce4+. The amphoteric Ce3+/Ce4+ ions can induce an in-situ diffuse phase transition at the Curie point of BaTiO3 (TC=125 °C). BC3TC5 exhibits a high-k behavior (ε′m=9470) and low dielectric loss (tan δ<0.025).