An energy level of 1.12eV was found here, which was proposed to dominate the dc degradation process of CaCu3Ti4O12 ceramics at high temperature and originated by the migration of oxygen vacancy. In addition, the levels of 0.09eV and 0.51eV were suggested to be bulk and domain boundary relaxations, respectively, which show no apparent change after dc electrical degradation. The level of 0.66eV was proposed to be grain boundary relaxation, which cannot be observed after degradation. The increment of permittivity after dc electrical degradation was resulted from the charges accumulation near the electrodes.

Defects and DC Electrical Degradation in CaCu3Ti4O12 Ceramics: Role of Oxygen Vacancy Migration. J.Li, X.Zhao, F.Gu, S.Li: Applied Physics Letters, 2012, 100[20], 202905