Structure determination of a planar defect in SrBi2Ta2O9

The atomic structure of a planar defect with a (001) habit plane in single crystal layered perovskite SrBi2Ta2O9 is determined by high-resolution Z-co ntrast imaging. We found that the defect forms a structure, with two Sr-Ta- O perovskite blocks connected by a metallic Sr-2 plane, rather than a Bi2O2 layer as in the perfect crystal. This defect is expected to be an efficien t hole trap and may have important implications for the electronic properti es and the ferroelectric response of the SrBi2Ta2O9 material. (C) 1999 Amer ican Institute of Physics. [S0003-6951(99)03039-9].