Variable temperature neutron diffraction study of crystal structure and transport pathways in oxide ion conductors Bi12.5Ln1.5ReO24.5 (Ln = Lu, Er)

Samples of highly conducting Bi12.5Lu1.5ReO24.5 and Bi12.5Er1.5ReO24.5 have been studied by neutron powder diffraction at room temperature for both phases and at 25 °C ≤ T ≤ 500 °C in the case of Bi12.5Er1.5ReO24.5. Both materials crystallize in the cubic δ-Bi2O3 related system, space group Fm-3m. Changes in the oxygen sublattice at 25 °C ≤ T ≤ 500 °C have been investigated by the Rietveld and maximum entropy methods.