Correlations between structure, microstructure and ionic conductivity in (Gd,Sm)-doped ceria
Cristina Artini, Massimo Viviani, Sabrina Presto, Sara Massardo, Maria Maddalena Carnasciali, Lara Gigli, Marcella Pani
Abstract
, and the expected positive effects of multiple doping. The main effect of double doping on the structure is the enlargement of the compositional region where ionic conductivity takes place, due to the entrance of the smaller doping ions into defect clusters, mainly trimers and dimers (RE ≡ rare earth). On the other hand, the formation of such clusters also affects ionic conductivity, as it causes the occurrence of a double activation energy with a temperature threshold located at ∼770 K. The dissociation of trimers above this temperature induces the appearance of a high temperature activation energy which is lower than the one observed in singly-doped systems, such as Sm- and Nd-doped ceria, showing the unique value of this parameter.