Interface and domain structures of (116)-oriented SrBi2Ta2O9 thin film epitaxially grown on (110) SrTiO3 single crystal

The interface and domain structure's in epitaxial (116)-oriented SrBi2Ta2O9 films on (110) SrTiO3 substrates were investigated by high-resolution transmission electron microscopy. The film contains domain boundaries due to the formation of two types of (116)-oriented crystallites with symmetrical tilted c-axis directions and numerous wavy c/6 translational boundaries originating from the domain boundaries. Each epitaxial crystallite forms a semicoherent interface accompanying periodic lattice strain, where the alternate continuity of perovskite layers in the film to the perovskite structure of SrTiO3 is found. Such a quasi-stable interface structure may be the primary cause of difficulty in the preparation of epitaxial SrBi2Ta2O9 films with the tilted c-axis.