Dresden 2006 – scientific programme
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O: Oberflächenphysik
O 40: Oxides and insulators
O 40.12: Talk
Thursday, March 30, 2006, 17:45–18:00, WIL A317
In-situ investigation of the Nb(110)/oxygen interface — •Melissa Delheusy1,2, Andreas Stierle1, Claire Antoine2, and Helmut Dosch1 — 1Max-Planck-Institut für Metallforschung, Heisenbergstr. 3, D-70569 Stuttgart, Germany — 2Commissariat à l’énergie atomique, Dapnia/SACM- Centre d’étude Saclay F-91191 Gif-sur-Yvette
Interstitial oxygen impurities are known to affect strongly the physical properties of Nb. This is of first importance for numerous superconducting high technology applications and in particular, for the future improvement of radio-frequency (RF) accelerating cavities. In-situ surface sensitive x-ray studies during oxidation and mild thermal treatments (RT-300∘C, UHV) of Nb(110) have been performed. Different aspects of the interaction oxygen/Nb were investigated in the first 50-100 nm below the surface, corresponding to the penetration length of a RF field in Nb. The oxide layer has been characterised by x-ray reflectivity; the depth-distribution of interstitial oxygen was studied with a nm-resolution by depth-resolved grazing incidence x-ray diffuse scattering; finally, the structure of the Nb/oxide interface was investigated by crystal truncation rods measurements. The experiments were realised at the Max-Planck-Institute surface diffraction beamline at the synchrotron source ANKA, and reveal an ordering of the interstitial oxygen atoms below the metal/oxide interface at 300∘C parallel to the dissolution of the oxide layer.