X-ray photoelectron spectra and composition of YBa2Cu3O7 − δ films prepared by laser ablation
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The Y3d, Ba3d 5/2, Cu2p 3/2, and O1s X-ray photoelectron spectra of thick (600 nm) superconducting YBa2Cu3O7 − δ films deposited on textured Ni-W substrates with Y2O3 + ZrO2 and CeO2 buffer layers have been studied. It has been established that, after the mechanical removal of surface layers with a diamond scraper (and as the analyzed region of the film approaches the interface), a decrease in the oxygen content leads to a decrease of the orthophase fraction and an increase of the tetraphase and Cu+ ion fractions. This is caused by the presence of elastic stresses in the superconducting film due to the lattice misfit between the phases making up a composite sample. These stresses prevent oxygen diffusion involved in oxidizing annealing. The spectra of the superconducting film have not revealed signals generated by elements of the substrate and buffer layers.
KeywordsBuffer Layer Lattice Misfit Y123 Phase CeO2 Buffer Layer Y123 Film
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