Relationship between Local Structure and Oxide Ionic Diffusion of Nd[2]NiO[4+δ] with K[2]NiF[4] Structure

Abstract

The relationship between the local structure and oxide ionic conduction of Nd[2]NiO[4+δ]possessing the K[2]NiF[4] structure was investigated. Various oxygen nonstoichiometry samples of Nd[2]NiO[4+δ] prepared with different annealing oxygen partial pressures were examined. The local structure related to oxide ionic conduction was determined by the Nd K-edge extended X-ray absorption fine structure. The oxide ionic conductivity and surface exchange coefficient were estimated using electronic conductivity relaxation methods. The activation energy for the oxide ionic conductivity was found to have a direct correlation to the surface exchange coefficient. The bottleneck size for oxide ion conduction was strongly correlated to the oxide ionic conduction of interstitial oxygen and the oxygen surface exchange rate.