Dielectric properties and nonlinear I-V electrical behavior of (Ni~(2+), Zr~(4+)) co-doping CaCu_3Ti_4O_(12) ceramics

摘要

Ni2+ and Zr4+ co-doped CaCu3Ti4O12 ceramics were successfully prepared by the sol-gel method. X-ray diffraction study reveals that single cubic perovskite CaCu3Ti4O12 phase was formed in all CaCu2.95Ni0.05Ti4-xZrxO12 samples. The SEM micrographs revealed that the microstructures change significantly with Ni2+/Zr4+ co-doping and sintering temperature while the average grain size grow up to 4.75 mu m for CaCu2.95Ni0.05Ti3.9Zr0.1O12 sample sintered at 1100 degrees C for 8h. Besides, all the samples show good nonlinear I-V electrical behavior. Further, the dielectric loss (tan) of CaCu2.95Ni0.05Ti3.9Zr0.1O12 sample shows the lowest value about 0.026 while the grain size reaches the maximum value. The dielectric constant (epsilon) tends to be independent of temperature range from 20 to 180 degrees C when the measured frequency is above 20kHz. These results indicate that Ni2+/Zr4+ co-doping can improve the dielectric and electrical properties of CaCu3Ti4O12.