Chemical composition and electronic structure of high-temperature superconductors: Ba/sub 2/EuCu/sub 3/O/sub 7-//sub x/ and La/sub 2-//sub x/Sr/sub x/CuO/sub 4/

Journal Article · Mon Feb 01 00:00:00 EST 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.37.1611· OSTI ID:5530801

Tang, M; Chang, Y; Onellion, M; Seuntjens, J; Larbalestier, D C; Margaritondo, G; Stoffel, N G; Tarascon, J M

We have studied the electronic structure of Ba/sub 2/EuCu/sub 3/O/sub 7-//sub x/ and La/sub 2-//sub x/Sr/sub x/CuO/sub 4/ (x = 0--0.15) with synchrotron-radiation photoemission and electron-energy-loss spectroscopy. The results were compared to those previously obtained on Ba/sub 2/YCu/sub 3/O/sub 7-//sub x/. The observed photoemission resonances are consistent with a prevailing Cu/sup 2+/ valence state for copper. Partial-yield spectra of Ba/sub 2/EuCu/sub 3/O/sub 7-//sub x/ indicate that the valence state of Eu is Eu/sup 3+/, and that of Ba is Ba/sup 2+/, similar to the corresponding elements in Ba/sub 2/YCu/sub 3/O/sub 7-//sub x/. From the energy-loss spectra, we derived plasmon energies and indications for peaks in the density of unoccupied states. The change in x for the La/sub 2-//sub x/Sr/sub x/CuO/sub 4/ samples only causes rigid shifts of the photoemission spectra.

• Research Organization: Department of Physics, Materials Science Program and Synchrotron Radiation Center, University of Wisconsin, Madison, Wisconsin 53706
• OSTI ID: 5530801
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 37:4
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
ELECTRONIC STRUCTURE
PHOTOEMISSION
COPPER OXIDES
EUROPIUM OXIDES
LANTHANUM OXIDES
STRONTIUM OXIDES
CHEMICAL COMPOSITION
ENERGY-LOSS SPECTROSCOPY
PLASMONS
SUPERCONDUCTORS
SYNCHROTRON RADIATION
VALENCE
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BREMSSTRAHLUNG
CHALCOGENIDES
COPPER COMPOUNDS
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
EMISSION
EUROPIUM COMPOUNDS
LANTHANUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
QUASI PARTICLES
RADIATIONS
RARE EARTH COMPOUNDS
SECONDARY EMISSION
SPECTROSCOPY
STRONTIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties