New La2/3TiO3 Derivatives: Structure and Impedance Spectroscopy

New phases which arise from inserting Na cations on the vacant A-sites of the compound La2/3TiO3 have been obtained, giving rise to the series La4/3-xNa3xTi2O6 (for x=0.16 and 0.28). These phases adopt a perovskite-type structure as deduced from their characterization by electron microscopy and neutron diffraction. Rietveld analyses show that the symmetry is orthorhombic (S.G. Ibmm). Electrical conductivity was determined by impedance spectroscopy, as a function of temperature. A similar behavior is observed for both samples, which behave as ionic conductors with activation energies of 0.92(3) and 0.92(5) eV, respectively.