A neutron total scattering study, coupled to pair distribution function analysis, was made of a Ga-based oxide-ion conductor that was characterized by interstitial oxygen migration. The study focussed on short-range order analysis of the defect structure in La1.50Sr0.50Ga3O7.25 with the aim of shedding light on the position of the interstitial oxygen and on the distortion induced in the structure by the extra-oxygen. The data analysis reveals that the preferred position, at low-temperature, for the interstitial oxygen was within the pentagonal ring formed by the Ga1 and Ga2 atoms and shifted with respect to the centre of the pentagon.

Interstitial Oxygen in the Ga-Based Melilite Ion Conductor: a Neutron Total Scattering Study. A.Mancini, C.Tealdi, L.Malavasi: International Journal of Hydrogen Energy, 2012, 37[9], 8073–80