Effect of Samarium on the Microstructure, Dielectric and Ferroelectric Properties of Barium Titanate Ceramics

Abstract

Samarium-doped barium titanate ceramics were prepared by the conventional solid-state reaction method. The microstructure, dielectric and ferroelectric properties of Sm-doped barium titanate ceramics have been investigated. The result indicates that Sm3+ ions enter the perovskite-type structure to substitute for Ba2+ ions on the A sites and lead to the change of the crystal structure from tetragonal to cubic structure. Addition of samarium can restrain the grain growth of barium titanate ceramics and lead to the fall of the Curie temperature. There is diffuse phase transition in Sm-doped barium titanate ceramics. Sm3+ ions can decrease the dielectric loss of barium titanate ceramics on the basis of the Ti-vacancy defect compensation model. The remnant polarization and the coercive field of Sm-doped barium titanate ceramics decrease monotonously with the increase of samarium content. As temperature rises, the remnant polarization and the coercive electric field of Sm-doped barium titanate ceramics decrease simultaneously. The remnant polarization and coercive electric field of barium titanate ceramics decrease with the increase of frequency. But the remnant polarization and coercive electric field of Sm-doped barium titanate ceramics have no evident change as frequency increases from 100 Hz to 1000 Hz.