ELECTRICAL-PROPERTIES OF LA1.33-XLI3XTI2O6 (0.1-LESS-THAN-X-LESS-THAN-0.3)

Structural characterization and ionic conductivity properties of three members of the La1.33-xLi3xTi2O6 (being x = 0.29, 0.21 and 0.09, resp ectively) perovskite-type series are reported. These phases are descri bed as tetragonal (S.G. P4/mmm) and the unit cell parameters (a approx imate to 3.87 and c approximate to 7.78 Angstrom) are related to the c ubic ABO(3) perovskite one. X-ray diffraction data were analyzed by th e Rietveld method and an interesting feature is that the cation vacanc ies are concentrated on alternating A-planes (i.e. for z = 1/2) of the structure. Therefore, cation mobility seems to be due to a 2-D mechan ism in such planes. Electrical properties have been measured by a.c. t echniques and the higher conductivity results were obtained for the in termediate composition, x approximate to 0.21. The activation energies of the three phases are quite similar. (C) 1998 Elsevier Science B.V. All rights reserved.