Conducting grain boundaries in the high-dielectric-constant ceramic CaCu3Ti4O12

Abstract

To clarify the electrical property of grain boundaries, the fine-grained ceramics CaCu3Ti4O12 have been treated with the hydrofluoric acid to remove the parts of grain boundaries. The dielectric response difference between the etched samples and the pristine ones indicates that the ceramic CaCu3Ti4O12 consists of insulating or semiconducting grains with conducting grain boundaries. Therefore, the giant dielectric phenomenon is supposed not to derive from the grain boundary barrier layer capacitance effect. The possible mechanism is discussed.