Measurements were made of the conductivity of single crystals having the space group, R¯3c. It was shown that a consideration of the crystal structure of a solid electrolyte could, in some cases, lead to quantitative predictions of the relative directional conductivities. The principal conductivities perpendicular to, and parallel to, the ¯3 axis were here equal to 0.0058 and 0.0031S/cm, respectively, at 300K. At 420K, the corresponding values were 0.043 and 0.021S/cm. On the basis of possible pathways through the crystal, the ratio of the principal conductivities had been predicted to be about 0.4. The measured ratio was close to 0.5, over the temperature range studied. The activation enthalpies for motion were equal to 0.21 and 0.20eV, respectively, perpendicular to and parallel to the ¯3 axis.

J.M.Gaines, S.Geller: Physical Review B, 1986, 34[12], 8963-6