title: Crystal structure and microstructure of some La(2/3-x)Li 3xTiO3 oxides: an example of the complementary use of electron diffraction and microscopy and synchrotron X-ray diffraction to study complex materials.
abstract: Three representative oxides of the La(2/3)(-)(x)()Li(3)(x)()TiO(3) system have been studied by selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM), and powder synchrotron X-ray diffraction. HRTEM showed that the materials have a complex microstructure. The SAED and HRTEM results have allowed us to propose a model to refine the crystal structure of these oxides that also accounts for their microstructure. The materials have a perovskite-related structure with a diagonal unit cell ( radical 2a(p) x radical 2a(p) x 2a(p)) as a consequence of the tilting of the TiO(6) octahedra. Ordering of lanthanum and lithium ions and vacancies along the 2a(p)-axis, as well as displacements of titanium ions from the center of the octahedra, have been determined. The size and shape of the domains have been obtained from the synchrotron X-ray diffraction data; in addition, other extended defects such as strains and compositional fluctuations have been detected.
authors.affiliation: Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense, 28040- Madrid, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: García-Martín
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Alario-Franco
authors.forename: Helmut
authors.initials: H
authors.lastname: Ehrenberg
authors.forename: Juan
authors.initials: J
authors.lastname: Rodríguez-Carvajal
authors.forename: Ulises
authors.initials: U
authors.lastname: Amador