Studies of electron energy loss spectroscopy and selected-area electron diffraction were systematically performed on 15 and 25at% lanthanide-doped ceria samples (Ln = Sm, Gd, Dy, and Yb), through which the local ordering of O vacancies that develops with increase in doping level was confirmed in the sequence of (Gd,Sm) > Dy > Yb. Furthermore, a monotone correlation between the development of the ordering and the degradation of ionic conductivity with increasing the doping concentration from 15 to 25at% was observed. Based on the analysis of selected-area electron diffraction patterns, a structural model for the ordering of O vacancies was constructed, in which the arrangement of O vacancies was similar to that in C-type Ln2O3 oxides and the ½<110> pairs of the vacancies were preferred.

Oxygen-Vacancy Ordering in Lanthanide-Doped Ceria - Dopant-Type Dependence and Structure Model. D.R.Ou, T.Mori, F.Ye, J.Zou, G.Auchterlonie, J.Drennan: Physical Review B, 2008, 77[2], 024108 (8pp)