EuNiO3 thin films- growth and characterization

We report on the process formation of EuNiO3 thin films on various substrates, studies of optimization conditions for synthesis process and primary investigation. EuNiO3 thin films were deposited by Radio Frequency Magnetron Sputtering in Ar-O atmosphere using a ceramic target with additional nickel pellets. We used Si, NdGaO3 and SrTiO3 substrates. Afterwards samples were annealed in high pressure and temperature in order to achieve a desired oxygen stoichiometry. Thickness of the film was controlled by deposition time and calculated by X-ray Reflectivity. X-ray diffraction measurements revealed that obtained thin films exhibit EuNiO3 phase on the surface still accompanied by Eu2NiO4 and NiO phases in the bulk. Therefore annealing seems to be a very surface sensitive process. That inhomogeneity was confirmed in X-ray photoemission depth profiling studies for EuNiO3/Si (60nm) thin film. Surface contamination with adsorbed oxygen has been observed with grazing angle analysis. Ni2p photoemission line analysis revealed a possible mixed-valence character of Ni electronic state.