Electrical behaviour of La1.33-xM3xTi2O6 perovskites (M=Li, Na and K)

Structural characterization and ionic conductivity properties of the La1.33 -xM3xTi2O6 (M=Li, Na and K) perovskite-type series are reported. From X-Ray diffraction data two different symmetries, tetragonal and orthorhombic, we re observed as a function of the ionic size of alkaline cations as well as their proportion in the compounds. Crystallographic features seem to influe nce on the two possible conduction mechanisms. Orthorhombic samples allow t he charge carriers motion through a 3D pathway whereas in the tetragonal on es mobile cations only can move into the A-planes in which are located. (C) 1999 Elsevier Science Ltd. All rights reserved.