X-ray Photoelectron Spectroscopy on Superconducting T1₂CaBa₂Cu₂O₈ Thin Film

We have prepared single-phase superconducting T1₂CaBa₂Cu₂O₈ thin film by dc magnetron sputtering process and measured X-ray photoelectron spectra of the film at room and liquid nitrogen temperatures. From the relative intensities of the Ba3d, Tl4f. O1 s and Cu2p spectra taken at different take-off angles, we have concluded that there is an adventitious contamination (nonsupercon-ducting phase) surface layer. After excluding contributions from these spurious phases, we have tentatively assigned which core-level shifts should be caused by the superconducting phase transition.