Synthesis and structural studies of cation-substituted Aurivillius phases ASrBi2Nb2TiO12

We report here a novel method to prepare high-quality samples of the three layered oxides ASrBi2Nb2TiO12ACa, Sr or Ba using the pre-formed intermediates ABi2Nb2O9 and SrTiO3. The room temperature structures were refined using synchrotron X-ray and Neutron powder diffraction data in the orthorhombic space group B2cb. This symmetry arises as a consequence of cooperative tilting of the BO6 octahedra in the [ASrNb2TiO10]2− perovskite-like slabs and a polar displacement of the cations. The structure is characterized by extensive cation disorder but lacks appreciable oxygen vacancies.

Details of the coordination environment of the Nb and Ti atoms.Figure optionsDownload as PowerPoint slide