Transport properties and defect analysis of La1.9Sr0.1NiO4 + δ

The oxygen flux through La1.9Sr0.1NiO4 + δ has been measured as a function of oxygen activity gradient and temperature (750-1000 °C). The oxygen nonstoichiometry was determined by thermogravimetry in the temperature range of 400-1000 °C and oxygen partial pressures of 0.0002-1 atm. The total conductivity was measured over a similar range of conditions. The oxide ion partial conductivity derived from the oxygen flux data is approximately 4 orders of magnitude lower than the total, mainly p-type electronic conductivity. The defect structure was derived based on the data. Combining the oxygen flux and oxygen nonstoichiometry, the self diffusion coefficient of oxygen interstitials was evaluated.