The structure of completely exchanged Na+/Pr3+ ”-alumina was investigated by using single-crystal X-ray diffraction methods at room temperature. The ionic distributions within the conducting planes were correlated with the crystal composition. It was found that up to 52% of the lanthanide ions occupied BR positions. The conductivity of crystals with various degrees of exchange was determined by means of impedance spectroscopy at temperatures ranging from 300 to 1000K. With increasing Pr3+ content, the ionic conductivity decreased and was associated with an increased activation energy. It was shown that, for a given degree of exchange, the conductivity exhibited a scatter of 1 to 2 orders of magnitude, while the activation energy ranged from 0.15 to 0.2eV. These variations were attributed to the effect of the various crystal compositions upon the thickness of the conduction slabs and the ionic distributions.

J.Köhler, W.Urland: Solid State Ionics, 1996, 86-88[1], 93-8