Structure and Dielectric Behavior of La-doped BaTiO3 Ceramics

摘要

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.