Defence Science Journal

The complex perovskite compound CaCu₃Ti₄O₁₂ (CCTO) is of considerable interest because of its anomalously large dielectric response. In this study, the dielectric properties of sol-gel-derived thin films of CCTO prepared at various annealing temperatures; 7000°C, 7200°C, and 7500°C have been reported. The frequency and temperature-dependent dielectric properties of all these samples have been studied in metal-insulator-metal configuration using an impedance analyser. Dielectric measurements at room temperature show that the dielectric constant increases with the increase in annealing temperature from 700°C–7500°C. High dielectric constant (varying from 600 to 3000 with the change in annealing temperature) has been observed at room temperature at 100 kHz. The dielectric measurements below room temperature do not show any evidence of structural relaxation in CCTO except a little additional tilting of the TiO₆ octahedra with decreasing temperature. The dielectric response of Ba-doped CCTO films has also been reported.