Investigation on Giant Dielectric Constant Material CaCu3Ti4O12

CaCu3Ti4O12 (CCTO), an unusual perovskite-like material, is known for extraordinarily high (often reaching 104) and relatively frequency independent dielectric constant. Recently, it has drawn a lot of attention, because of its potential applications in microelectronics and microwave devices.;In this investigation, CCTO powders were synthesized by two routes, a conventional solid-state reaction and a wet-chemistry method. Three kinds of materials, polyvinyl alcohol (PVA, an organic binder), boric oxide (B 2O3, a well-known glass former), hafnium oxide (HfO 2, a material with high dielectric constant ∼25), were added to the pre-reacted CCTO powder and sintered into ceramics. The effects of these additives on the microstructures, or electric and dielectric properties of CCTO ceramics were investigated. In addition, CCTO thin films were also successfully prepared. The AC conductivity, impedance, and complex dielectric permittivity were used to analyze the data. These observations were well explained in terms of an internal barrier layer capacitor (IBLC) model with Maxwell-Wagner (MW) dielectric relaxation.