Synthesis and structural studies of cation-substituted Aurivillius phases ASrBi(2)Nb(2)TiO(12)

摘要

We report here a novel method to prepare high-quality samples of the three layered oxides ASrBi(2)Nb(2)TiO(12) A = Ca, Sr or Ba using the pre-formed intermediates ABi(2)Nb(2)O(9) and SrTio(3). 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 [ASrNb(2)TiO(10)](2-) perovskite-like slabs and a polar displacement of the cations. The structure is characterized by extensive cation disorder but lacks appreciable oxygen vacancies. (c) 2006 Elsevier Inc. All rights reserved.