Oxygen vacancy ordering in heavily rare-earth-doped ceria.

25 at. % Rare-earth (RE)-doped ceria samples (RE=Sm, Dy, Y, and Yb) were examined using transmission electron microscopy and electron energy loss spectroscopy, from which the oxygen vacancy ordering in nanosized domains was confirmed. The relationships of the dopant type, oxygen vacancy ordering, and ionic conductivity of doped ceria were established. It is found that the ordering of oxygen vacancies depends strongly on the dopant type, and the development of nanosized domains with a higher degree of ordering can lead to a more dramatic decrease of ionic conductivity in doped ceria. [ABSTRACT FROM AUTHOR]