Structural and electrical characterisation of lanthanum nickelate reactively sputter-deposited thin films

La2NiO4 coatings were co-sputtered on rotating substrates from metallic La and Ni targets in the presence of a reactive argon–oxygen gas mixture. This material is a potential candidate as cathode material for Intermediate Temperature-Solid Oxide Fuel Cells. The structural and chemical features of these films have been determined by X-ray Diffraction and Scanning Electron Microscopy. Their electrical properties have been characterised using the four point probe method and by Complex Impedance Spectroscopy measurements.It is shown that the as-deposited coatings, initially amorphous, crystallise in the LaNiO3 perovskite-type oxide or in the convenient K2NiF4 structure as a function of their composition. The electrical measurements show a clear relation between resistivity and structure of the coatings. Despite electrical resistivity values close to the theoretical ones, the activation energy of a coating presenting the convenient K2NiF4 structure is slightly higher than those given in the literature data.