Direct observations of La ordering and domain structures in La0.61Li0.17TiO3 by high resolution electron microscopy.

La0.61Li0.17TiO3 microstructures have been studied by high resolution electron microscopy. A local lattice distortion occurs in the vicinity of the domain boundary region due to the twin with an angle of 89°. The average domain size of La0.61Li0.17TiO3 is greater than 20 nm. The domain size and structures of La0.61Li0.17TiO3 differ greatly from those of La-poor compounds, such as La0.55Li0.35TiO3. At a nanoscopic level, microdomains of 20-100 nm in size construct a two-dimensional structure in La-rich compounds, while microdomains of 5-10 nm in size construct a three-dimensional structure in La-poor compounds. In addition, the Li-ion conduction mechanisms for La-rich and La-poor compounds are two- and three-dimensional, respectively. [ABSTRACT FROM AUTHOR]