High-permittivity and conduction mechanism of La-doped Ba_(0.67)Sr_(0.33)TiO_3 ceramics

摘要

High permittivity La-doped Ba_(0.67)Sr_(0.33)TiO_3 ceramics (BSTL) with cubic perovskite structure, i.e., Ba_xSr_(1-X)TiO_3 (BST) + x at.% La, where x = 0-1, were prepared by conventional ceramic processing techniques. Dielectric characteristics, X-ray diffraction, scanning electron microscopy (SEM), and J-VV (leakage current density–voltage) behaviors were measured. Doping with the La in the BST host lattice resulted in a large-grained (1-3 um) and fine-grained (0.3-1 um) microstructure,marked raising, and broadening of the Curie peak. The temperature of dielectric peak (T_m) at 10 kHz decreased rapidly with a doping concentration of <0.7 at.% La. By means of doping with La, high dielectric constant ceramics STL: 0.2 110 000 at 10 kHz have been achieved. The plots of leakage current density versus voltage show the different voltage ranges.