Münster 1999 – scientific programme
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O: Oberflächenphysik
O 11: Poster (I)
O 11.30: Poster
Monday, March 22, 1999, 19:30–22:30, Aula
Surface Analysis and Ageing of YBa2Cu3O7−δ, NdBa2Cu3O7−δ and Bi2Sr2CaCu2O8+δ single crystals — •P. Henzi1, M. Regier1, D. Schild1, T. Wolf1, A. Erb2, and J. Halbritter1 — 1Forschungszentrum Karlsruhe, Hermann von Helmholz-Platz 1 — 2DPMC, Universität Genf, 24, quai Ernest Ansermet, CH-1211 Genf
Because clean is defined by the knowledge of
Schmutz, we carried out angle resolved X-ray photoelectron
spectroscopy (ARXPS)-measurements on single crystals. Despite
superconductivity being observed by STM and STS at single crystal
surfaces, reaction cinder in thicknesses above 1–2 nm has been
observed. ARXPS analysis using the Ba-4d core level and its
chemical shifts, taking the surface reconstruction into account,
shows a corrosion layer, which yields the large leakage current on
those crystals.
With time in air, aside of the above mentioned
corrosion layer, starting with Ba-,Sr-hydroxides as first step,
adsorption consisting of hydroxides and carbonates shows up.