Local Ordering in Praseodymium/Gadolinum Co-doped Ceria MIECs

Gadolinium doped ceria is currently being used as an oxide ion conducting electrolyte in intermediate temperature solid oxide fuel cells (SOFCs). When co-doped with praseodymium or at lower oxygen partial pressures (pO2), these materials can also act as mixed ionic-electronic conductors (MIECs). Gd based compounds are not usually studied by neutron methods because of the high absorption cross section of natural Gd. However, using samples isotopipcally enriched with 160Gd (which has a low absorption cross section) we propose to study the local order in Gd/Pr co-doped cerias. In partciular, we seek to establish whether the samples show ordering on the anion and/or cation sublattices and whether there is evidence for dopant segration at the grain boundaries that is seen in previous studies of Pr doped ceria.