It was found that the O diffusivity in doped perovskites, which were among the best O conductors, could be further enhanced - by some orders of magnitude - by inducing crystallographic ordering among lanthanide and alkali-earth ions in the A-site sub-lattice. The transformation of a simple cubic perovskite with randomly occupied A-sites, into a layered crystal with alternating lanthanide and alkali-earth planes, reduced the O bonding strength and created disorder-free channels for ion motion; thus suggesting an efficient means for designing new ionic conductors.

Fast Oxygen Diffusion in A-Site Ordered Perovskites. A.A.Taskin, A.N.Lavrov, Y.Ando: Progress in Solid State Chemistry, 2007, 35[2-4], 481-90