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

Abstract

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 (ϵr) ∼2450 and dielectric loss (tanδ) ∼0.5 at frequency of 1 kHz and 20°C were observed for the BFN ceramic samples. Higher value of ϵr ∼ 3600 and lower value of tan δ ∼ 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 ϵr and sharp increase of tan δ at higher frequencies of BFN ceramic samples indicated the presence of Debye like relaxation.