Abstract
In ferroelectrics, it is sometimes observed that the local structure is different from the average structures. We observed the difference between the local and average structure of Bi4Ti3O12. The average and local structures were refined by Rietveld and Pair-distribution function (PDF) analysis, respectively. These were refined with the same data set collected by high-energy synchrotron X-ray diffraction. The crystal symmetry of both the local and average structures of Bi4Ti3O12 was orthorhombic. The TiO6 rotation angle around the b-axis of the local structure was larger than that of the average structure. The difference should originate from oxygen vacancies, which are generated in crystal synthesis.