Improved giant dielectric properties in microwave flash combustion derived and microwave sintered CaCu3Ti4O12 ceramics
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The nanocrystals of CaCu3Ti4O12 ceramic were prepared by microwave flash combustion technique. The microwave sintering of powders was optimized to 1025 − 1075 °C for 20 min with heating and cooling rate of 50 °C/min. Microstructural evaluation of sintered sample was carried out using SEM. The dielectric properties were measured in the frequency range 10–2 × 106 Hz and the temperature range 30–100 °C. The CCTO sample sintered at 1075 °C had giant dielectric constant 53,300 at 100 Hz. It was observed that dielectric constant was greatly increased on a slight increase in sintering temperature. Modulus and impedance analysis were performed to explore the observed unusual dielectric response. Grain and grain boundary resistance were observed as 8 Ω and 350,000 Ω, respectively. The grain boundary activation energy for electro-conduction was calculated as 0.65 eV by using the characteristic frequencies in cole-cole plots. It was noticed that the thermally activated charge carriers had long-range mobility.
KeywordsCeramic Microwave flash combustion Microwave sintering Dielectric properties
Ranjit Kumar is thankful to Council of Scientific and Industrial Research (CSIR), India for funding to carry out this research work.
- 4.D.C. Sinclair, T.B. Adams, F.D. Morrison, A.R. West, App. Phys. Lett. 80, 2153 (2002)Google Scholar
- 13.P. Delugas, P. Alippi, V. Fiorentini, V. Raineri, Phys. Rev. B 81(81104) (2010)Google Scholar
- 22.P. Thongbai, C. Masingboon, S. Meansiri, T, Yamwong, S. Wongsaenmai, R. Yimnirun, J. Phys.: Condens. Matter 19, 236208 (2007), 23Google Scholar