Atomic-scale structure of nanocrystalline BaxSr1-xTiO3 (x=1, 0.5, 0) by X-ray diffraction and the atomic pair distribution function technique

The atomic-scale structure of nanocrystalline BaxSr1-xTiO3 (X = 1, 0.5, 0) powders has been studied using high-energy X-ray diffraction, Rietveld refinement, and the atomic pair distribution function technique. The studies show that the materials are well-ordered at nanometer length distances. The three-dimensional atomic ordering in Ba0.5Sr0.5O3 and SrTiO3 nanopowders may well be described by a cubic structure of the perovskite type, similar to that occurring in the corresponding bulk crystals. The three-dimensional atomic ordering in BaTiO3 is more complex. It is cubic-like on average, but locally shows slight distortions of a tetragonal-type. The new structural information helps one to understand better the dielectric properties of these nanomaterials.