Cu valence and the formation of high T/sub c/ superconductor oxides studied by x-ray photoemission spectroscopy on 200 A Bi-Sr-Ca-Cu oxide thin films

Journal Article · Mon Jan 23 04:00:00 EST 1989 · Appl. Phys. Lett.; (United States)

DOI:https://doi.org/10.1063/1.100971· OSTI ID:6619583

Yeh, J; DiCenzo, S B; Hartford, Jr, E H; Hong, M; Felder, R J

We have used x-ray photoemission spectroscopy to study the core level spectra of 200 A Bi-Sr-Ca-Cu oxide thin films, in the hope that the importance of the surface sensitivity of photoemission is minimized for these samples, whose thickness is only 6--7 unit cells. The samples were annealed in oxygen at temperatures ranging from 600 to 870 /sup 0/C, over which temperature range the thin films are converted from an amorphous insulating phase to an ordered superconducting phase with T/sub c/ (R = 0) = 80 K. Regardless of the annealing temperature, the Cu 2p spectra of all films show satellite structure indicative of Cu/sup 2 +/ states. Even the spectrum of an as-deposited film has a satellite similar to those observed for the annealed films, including the superconducting film. The similarity of the satellite structure in the core level spectra for all films suggests that the Cu-O interactions, such as the Cu d-O p orbital charge transfer energies and the hopping integrals, remain similar when the oxides undergo the insulator-superconductor transition through high-temperature anneal. That is, the same local Cu-O interaction exists before and after the superconducting phase sets in. This implies that the Cu valence alone does not determine the properties of high T/sub c/ superconductors.

• Research Organization: ATandT Bell Laboratories, Murray Hill, New Jersey 07974
• OSTI ID: 6619583
• Journal Information: Appl. Phys. Lett.; (United States), Journal Name: Appl. Phys. Lett.; (United States) Vol. 54:4; ISSN APPLA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201 -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204* -- Ceramics
Cermets
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656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
AMORPHOUS STATE
ANNEALING
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
DATA
DIMENSIONS
ELECTRON SPECTROSCOPY
EMISSION
EXPERIMENTAL DATA
FABRICATION
FILMS
HEAT TREATMENTS
HIGH TEMPERATURE
INFORMATION
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
PHOTOEMISSION
SECONDARY EMISSION
SPECTROSCOPY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTING FILMS
SYNTHESIS
THICKNESS
THIN FILMS
TRANSITION ELEMENT COMPOUNDS
VALENCE
VERY HIGH TEMPERATURE