X-ray photoelectron spectra and composition of YBa2Cu3O7 − δ films prepared by laser ablation
The Y3d, Ba3d5/2, Cu2p3/2, 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.
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- 4.N. M. Plakida, High-Temperature Superconductivity: Experiment and Theory (Springer-Verlag, Berlin, 1994; International Program of Education, Moscow, 1996).Google Scholar
- 5.H. W. Seo, Q. Y. Chen, P. van der Heide, and W. K. Chu, http://arxiv.org/ftp/cond-mat/papers/0603/0603767.