Electric and dielectric properties of Bi-doped CaCu_3Ti_4O_(12) ceramics

摘要

Pure and Bi-doped Bi_xCaCu_3Ti_4O_(12+1.5x) (BCCTO, x=0, 0.15, 0.25, and 0.3) ceramics were fabricated by the solid-state sintering method. The results indicate that the additional bismuth has a great influence on both the microstructures and the electric properties. A new phase (Bi_4Ti_3O_(12)) can be observed in the doped samples from the x-ray diffraction patterns. Additionally, the CCTO gain size can be controlled by bismuth content. All of the BCCTO samples show high dielectric permittivity (～ 10~4 at 10~3 Hz) and varistor effect, and the relaxation peak shifts to higher frequency. The resistance rises with the increase in bismuth, and the activation energy at the grain boundary is reduced from 0.65 to 0.47 eV.