X-ray photoelectron spectroscopy study of thin Ag overlayers on YBa sub 2 Cu sub 3 O sub 7 minus x : Effects of oxygen annealing

Journal Article · Wed Aug 15 00:00:00 EDT 1990 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.346608· OSTI ID:6766710

Niedermann, P; Grande, A P; Grepstad, J K ^[1]; Triscone, J; Karkut, M G; Brunner, O; Antognazza, L; Sadowski, W; Scheel, H J; Fischer, O ^[2]

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1. University of Trondheim-NTH and ELAB-RUNIT, N-7034 Trondheim (Norway)
2. Universite de Geneve, Departement de Physique de la Matiere Condensee, quai E.Ansermet 24, CH-1211 Geneve 4 (Switzerland)

X-ray photoelectron spectroscopy was used to examine vapor deposited Ag overlayers on YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} thin films and cleaved single-crystal surfaces ({ital x}=1), including the effects of subsequent heat treatment in oxygen. The core level spectra of the present tetragonal crystals were found to closely resemble those previously reported for nominally orthorhombic superconducting samples. Minor differences, notably an increased fraction of Cu in the +1 oxidation state and a slightly higher binding energy of the Ba 3{ital d} levels, may be attributed to the lower oxygen content of the tetragonal semiconducting phase. Deposition of Ag on clean monocrystal surfaces was found to cause some disruption of CuO bonds at the Ag/YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} interface. We also find weak indications of surface band bending (i.e., Schottky barrier formation) from a uniform shift in the measured binding energies of the substrate core levels upon Ag deposition. Heat treatment in pure oxygen (1 h at 500 {degree}C) of Ag-coated superconducting thin films was found to reduce efficiently the amount of superficial contaminant phases, initially present on the air-exposed thin-film surfaces, and to cause diffusion of Ag to a depth of {similar to}20 nm into the volume of the material.

• OSTI ID: 6766710
• Journal Information: Journal of Applied Physics; (USA), Vol. 68:4; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
ANNEALING
VAPOR DEPOSITED COATINGS
COPPER OXIDES
SILVER
DIFFUSION
YTTRIUM OXIDES
ELECTRONIC STRUCTURE
FILMS
HIGH-TC SUPERCONDUCTORS
LAYERS
MONOCRYSTALS
OXYGEN
PHOTOELECTRON SPECTROSCOPY
SURFACES
X RADIATION
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COATINGS
COPPER COMPOUNDS
CRYSTALS
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
ELEMENTS
HEAT TREATMENTS
IONIZING RADIATIONS
METALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
RADIATIONS
SPECTROSCOPY
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YTTRIUM COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties