Dresden 2003 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
O: Oberflächenphysik
O 24: Postersitzung (Epitaxie und Wachstum, Oxide und Isolatoren, Elektronische Struktur, Oberfl
ächenreaktionen, Adsorption an Oberfl
ächen, Organische Dünnschichten)
O 24.20: Poster
Mittwoch, 26. März 2003, 14:30–17:30, P1
X-ray Standing Waves and Photoemission Studies of GdBa2Cu3O7 − δ HTS Thin Films — •Sebastian Thiess, T.L. Lee, L.X. Cao, S. Warren, B.C.C. Cowie, and Jörg Zegenhagen — ESRF, Grenoble, France
Photoemission has been widely used for probing electronic properties of materials. With x-ray photoelectron spectroscopy (XPS) from core and valence-band states excited by an x-ray standing wave (XSW) field, site-specific electronic information, originally not available from standard XPS, can be obtained. This allows to identify the chemical origins of different features observed in photoemission spectra. In the present study, we employed XSW to characterize the interfacial structure as well as the electronic properties of epitaxial high-temperature superconductor (HTS) thin films. Ultra-thin films of the 90K superconductor GdBa2Cu3O7 − δ were grown by pulsed-laser deposition on single crystal NdGaO3(001) substrates. Measurements were carried out at room-temperature at beamline ID32 of the ESRF using an x-ray energy of 3.2 keV. The XSW analysis of Nd and Ga core-levels from the interfaces suggest diffusion of Nd into the HTS films. A chemically shifted O1s peak towards higher binding energy is indicative of surface contamination due to air exposure during the transfer. The XSW analysis allows to determine the CuO-NdO interfacial distance to be 0.19 nm, identical to the NdO-GaO2 spacing of NdGaO3. The XSW analysis of the Cu3d and O2p valence band contributions will be discussed.