Microwave assisted sol-gel synthesis of high dielectric constant CCTO and BFN ceramics for MLC applications

Ba(Fe1/2Nb1/2)O3 (BFN) and CaCu3Ti4O12 (CCTO) ceramic powders were synthesized by microwave assisted sol-gel synthesis technique and sintered at 1100?C and 1000?C, respectively. Calcination and sintering processes were carried out in a microwave furnace. Dielectric constant (?r)~2450 and dielectric loss (tan ?)~0.5 at frequency of 1 kHz and 20?C were observed for the BFN ceramic samples. Higher value of ?r ~ 3600 and lower value of tan ? ~ 0.07 at frequency of 1 kHz and in 20-60?C temperature range for the CCTO ceramic samples suggested its utility for MLC applications. Sharp decrease of ?r and sharp increase of tan ? at higher frequencies of BFN ceramic samples indicated the presence of Debye like relaxation.