Dielectric and piezoelectric properties of cerium modified BaBi_4Ti_4O_(15) ceramics

摘要

Cerium modified barium bismuth titanate ceramics BaBi_4Ti_4O_(15-x)CeO_2 (wt%) were prepared by a solid-state reaction method. X-ray diffraction patterns showed that the ceramics have a four-layer Aurivillius-type structure with orthorhombic phase at room temperature. The plate-like morphology with average grain size about 2 μm was observed by scanning electron microscope (SEM). The effects of cerium modification on dielectric and piezoelectric properties of BaBi_4Ti_4tO_(15) ceramics were studied. The results showed that cerium modification enhanced the piezoelectric properties, decreased the temperature of the dielectric maximum (T_m) slightly from 413℃ to 406℃ and the dielectric loss, tan 5, as well. The modified Curie-Weiss law was used to describe the relaxor behavior of the ceramics and the degree of dielectric relaxation (γ) firstly increases then decreases with the cerium increasing. The relaxor nature was attributed to the A-site cationic disorder.