Structural and microstructural studies of the series La2/3-xLi3x square 1/3-2xTiO3

Much work has been done on the series La(2/3-x)Li(3x)square(1/3-2x)TiO(3) because of the high level of Li+ ionic conductivity exhibited by this material. Curiously, the structural aspect was not yet really explored. We propose here a structural model for the series, in the composition range 0.06 < x < 0.14, on the basis of X-ray powder diffraction and transmission electronic microscopy data: the symmetry is tetragonal (P4/mmm), and the unit cell derives from that of the perovskite ABO(3) (a = a(p), c similar to 2a(p)). Vacancies, La, and Li ions are unequally distributed on two sites, 1a and 1b; the La distribution is approached by the Rietveld method from the X-ray powder patterns and confirmed by simulation of high resolution electron microscopy images. (C) 1996 Academic Press.