Résumé du preprint Irfu-08-51

Irfu-08-51
X-ray investigation of subsurface interstitial oxygen at Nb/oxide interfaces
M. Delheusy, A. Stierle, N. Kasper, R. P. Kurta, A. Vlad, H. Dosch, C. Antoine, A. Resta, E. Lundgren, J. Andersen
We have investigated the dissolution of a natural oxide layer on a Nb110 surface upon heating, combining x-ray reflectivity, grazing incidence diffuse scattering, and core-level spectroscopy. The natural oxide reduces after heating to 145 °C partially from Nb2O5 to NbO2, and an enrichment in subsurface interstitial oxygen by 70% in a depth of 100 Å is observed. After heating to 300 °C, the oxide reduces to NbO and the surplus subsurface oxygen gets dissolved into the bulk. Our approach can be applied for further investigation of the effect of subsurface interstitial oxygen on the performance of niobium rf cavities.