Extensive regions of cubic fluorite solid-solution formation were observed in these systems. Conductivity studies indicated that the activation energy for conduction increased rapidly, and the high-temperature conductivity decreased, as the Y2O3 content increased. However, at high defect concentrations the activation energies tended towards a constant value. The increase in activation energy was related to an increase in the extent of diffuse reflections in neutron diffraction experiments, and to increases in the isotropic temperature factor which were associated with the anion sub-lattice. A significant negative correlation was observed between the conductivity pre-factor and O temperature factor. Electron diffraction experiments revealed diffuse elements in addition to the cubic fluorite structure; thus indicating the presence of a short-range order that was related to C-type and distorted pyrochlores.

Structural Studies of the Optimisation of Fast Oxide Ion Transport. J.T.S.Irvine, A.J.Feighery, D.P.Fagg, S.Garcia-Martin: Solid State Ionics, 2000, 136-137, 879-85