J. Phys. Colloques
Volume 48, Numéro C9, Décembre 1987X-Ray and Inner-Shell Processes
|Page(s)||C9-1189 - C9-1192|
J. Phys. Colloques 48 (1987) C9-1189-C9-1192
HIGH ENERGY SPECTROSCOPIES OF Cu COMPOUNDS, INCLUDING THE NEW SUPERCONDUCTORSM. GRIONI1, 2, J.C. FUGGLE1, P.J.W. WEIJS1, J.B. GOEDKOOP1, G. ROSSI2, F. SCHAEFERS3, J. FINK4 and N. NÜCKER4
1 Research Institute for Materials, University of Nijmegen, The Netherlands
2 LURE, Université Paris-Sud, F-91405 Orsay Cedex. France
3 Berliner Elektronenenspeicherring-Gesellschaft für Synchrotronstrahlung mbH (BESSY), D-1000 Berlin 33, F.R.G.
4 Kernforschungszentrum Karlsruhe, Institut für Nukleare Festkörperphysik, Karlsruhe. F.R.G.
High energy spectroscopies are well suited to address the controversial issue of Cu valence in the new high Tc superconductors, as they can discriminate between various possible Cu configurations (d8, d9 or d10). XAS, XPS and AES spectra of CuI, CuII and CuIII compounds show that, as a results of hybridization, the actual Cu d-count can be quite different from what is expected from simple considerations based on the formal valence. A value of ~ 9.3. is inferred electrons for the superconducters. Discrepancies in the published results are attributed to insufficient sample characterization : we propose to adopt the O is XPS signal as a standard probe of surface condition in these materials.