Convergent-beam electron diffraction study of the local structure of the tetragonal phase of PbTiO₃

Recently, nanometer-scale local structures with rhombohedral symmetry were discovered in BaTiO₃ and KNbO₃ using convergent-beam electron diffraction (CBED). In the present study, it has been examined using the CBED method whether such local structures exist in PbTiO₃. It has been found that the symmetries of CBED patterns of the ferroelectric tetragonal phase of PbTiO₃ agree with those expected from the tetragonal structure reported by X-ray crystal structure analysis. That is, the present study has revealed that such nanostructures as observed in BaTiO₃ and KNbO₃ do not exist in the tetragonal phase of PbTiO₃.