Effects of (Li,Ce) on the Dielectric, Piezoelectric and Impendence Properties of CaBi4Ti4O15 Piezoceramics

Abstract

Aurivillius phase (Li,Ce) doped CaBi4Ti4O15 (CBT) ceramics were prepared using the conventional solid state methods. The crystal structure and microstructure were determined by X-ray diffraction and scanning electron microscopy. It was found that the (Li,Ce) ions diffused into the A site of CBT's pseudo-perovskite structure and formed a single Aurivillius type structure. The Curie-temperature (T C) of CBT based ceramics decreased whereas the piezoelectric coefficient (d 33) was improved with an increase of (Li,Ce) dopants. The detailed electrical properties for Ca0.85(LiCe)0.075Bi4Ti4O15 ceramics in the high temperature region were determined using electrochemical impedance spectra. It was found that oxygen vacancies make a major contribution to both electrical conduction and dielectric relaxation. The ac conductivity was found to obey Jonscher's universal law. In addition, the physical nature of electrical conduction and dielectric relaxation was addressed in this paper.