Structure and Dielectric Behavior of La-Doped BaTiO<sub>3</sub> Ceramics

Abstract

BaTiO3 ceramics doped with 1, 2, 3 and 4 mol% La were prepared by sol-gel method. The effects of La doping on structure and dielectric characteristics of Ba1−xLaxTiO3 were investigated. The results show that: All the powders calcined at 800°C were found to be perovskite structure with cubic phase. Ba1−xLaxTiO3 were sintered at 1300°C, phase transition behavior appeared from tetragonal phase to cubic phase with increasing La-doping level. As the doping concentration increases, the grain growth of the Ba1−xLaxTiO3 ceramics was controlled efficiently and Curie point shifted to lower temperature. The grain size decreased from 20μm with 0 mol% La doped to 0.5μm with 4 mol% La doped. The Curie point shift rate was 22 °C/ mol% with increasing La content. The dielectric constant of La doped Ba1−xLaxTiO3 ceramics increased with increasing La content and a maximum value of 8900 was attained with 4 mol% La doped.