Pure Bi4Ti3O12 ceramics were prepared by using the conventional solid-state reaction method and their dielectric properties were investigated. A dielectric loss peak with the relaxation-type characteristic was observed at about 370K and 100Hz. This peak was confirmed to be associated with the migration of O vacancies inside ceramics. The Cole–Cole fitting to this peak revealed a strong correlation among O vacancies and this strong correlation was considered to commonly exist among O vacancies in ferroelectrics. Therefore, the migration of O vacancies in ferroelectric materials would demonstrate a collective behavior instead of an individual one due to this strong correlation. Furthermore, this correlation was in proportion to the concentration and in inverse proportion to the activation energy of O vacancies. These results could be helpful to the understanding of the fatigue mechanisms in ferroelectric materials.

Correlation Among Oxygen Vacancies in Bismuth Titanate Ferro-Electric Ceramics. W.Li, K.Chen, Y.Yao, J.Zhu, Y.Wang: Applied Physics Letters, 2004, 85[20], 4717-9