Improved dielectric and non-ohmic properties of Ca2Cu2Ti4O12 ceramics prepared by a polymer pyrolysis method

Non-ohmic and dielectric properties of Ca2Cu2Ti4O12 (CaCu3Ti4O12/CaTiO3 composite) ceramics prepared by a polymer pyrolysis method (PP-ceramic samples) are investigated. The PP-ceramics show a highly dense structure and improved non-ohmic and dielectric properties compared to the ceramics obtained by a solid state reaction method (SSR-ceramic samples). epsilon' (tan delta) of the PP-ceramic samples is found to be higher (lower) than that of the SSR-ceramic samples. Interestingly, the PP-ceramic sintered at 1050 degrees C for 10 h exhibits the high epsilon' of 2530 with weak frequency dependence below 1 MHz, the low tan delta less than 0.05 in the frequency range of 160 Hz-177 kHz, and the little temperature coefficient, i.e., vertical bar Delta epsilon'vertical bar <= 15% in the temperature range from -55 to 85 degrees C. These results indicate that the CaCu3Ti4O12/CaTiO3 composite system prepared by PP method is a promising high-epsilon' material for practical capacitor application. (C) 2011 Elsevier B.V. All rights reserved.