Oxygen exchange kinetics and nonstoichiometry of pristine La0.6Sr0.4CoO3-δ thin films unaltered by degradation

La0.6Sr0.4CoO3-delta thin films grown on YSZ single crystals were investigated directly in the stage of deposition by means of in situ impedance spectroscopy during pulsed laser deposition (IPLD). This method allows the observation of dense thin films unaltered by degradation and provides information about the oxygen exchange kinetics as well as the defect chemistry of pristine LSC thin films. These measurements revealed remarkably low surface resistance values (1.3 omega cm(2) at 600 degrees C and 0.04 mbar O-2) compared to films measured outside the PLD chamber (similar to 20 omega cm(2) at 600 degrees C and 0.04 mbar O-2). Also the activation energy of the surface exchange resistance at 0.04 mbar p(O-2) is significantly lower than at ambient conditions (similar to 1 eV vs. similar to 1.3 eV) and degradation happens considerably slower. Furthermore, the grain size of the LSC thin film does not affect its initial surface resistance directly after deposition. The chemical capacitance of LSC thin films was linked to the concentration of oxygen vacancies and shows that LSC thin films exhibit lower oxygen vacancy concentrations than the corresponding bulk material.