Dielectric relaxation properties of nanostructured Ce0.8Gd0.1Pr0.1O2-δ material at intermediate temperatures

The dielectric relaxation behavior of the fluorite structured nanocrystalline Ce0.8Gd0.1Pr0.1O2-delta compound was studied in the temperature range of 200-550 degrees C. Two different types of relaxation processes were observed corresponding to (1) defect pairs such as (Pr-Ce(')-V-O)(center dot) and (Gd-Ce(')-V-O)(center dot) and (2) the trimers such as (Pr-Ce(')-V-O(center dot center dot)-Gd-Ce(')). The correlation between ionic conduction and the dielectric properties of the nanocrystalline material is discussed. Very low values of the migration energy and association energy of the oxygen vacancies are observed, which are 0.42 and 0.03 eV, respectively. The obtained value of association energy agrees well with the theoretical prediction on doubly doped ceria.