Enhanced grain size effect on electrical characteristics of fine-grained BaTiO3 ceramics

Abstract

Fine-grained BaTiO3 ceramics with different grain sizes (96–194 nm) were prepared by microwave sintering, and the grain size (GS) effect of fine-grained BaTiO3 ceramics on the electrical properties were investigated. A change from the tetragonal to pseudocubic structure gradually takes place with the decrease of GS. As the GS increased from 96 to 194 nm, the dielectric constant increased from 1300 to 1560. The temperature capacitance coefficients satisfied the EIA X7R specifications for all the samples. Impedance analysis proved that the fine-grained ceramics have higher activation energy for both grain and grain boundary. The remnant polarization (P r ) values decrease with the decreasing of the GS, which is ascribed that the increasing of the grain boundary and internal stress would weaken the polarization of the direction of electric field. The grain boundary and defects have the pinning effects on the domain, leading the increase in E c .