Local structure of BaBi sub x Pb sub 1 minus x O sub 3 determined by x-ray-absorption spectroscopy

Journal Article · Tue Oct 01 04:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.44.6961· OSTI ID:5294189

Boyce, J B ^[1]; Bridges, F G ^[2]; Claeson, T ^[3]; Geballe, T H ^[4]; Li, G G ^[2]; Sleight, A W ^[5]

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1. Xerox Palo Alto Research Center, Palo Alto, California (USA)
2. Department of Physics, University of California, Santa Cruz, California (USA)
3. Physics Department, Chalmers University of Technology, S-41296 Goeteborg (Sweden)
4. Department of Applied Physics, Stanford University, Stanford, California (USA)
5. Department of Chemistry, Oregon State University, Corvallis, Oregon (USA)

X-ray-absorption fine-structure (XAFS) spectroscopy was employed to study the near-neighbor environments of the Bi and Pb atoms in the perovskite-structured material BaBi{sub {ital x}}Pb{sub 1{minus}{ital x}}O{sub 3}, for {ital x}=1, 0.75, 0.5, and 0.25. For the semiconducting end member, BaBiO{sub 3}, two Bi-O distances, separated by 0.18 A, could be distinguished, consistent with diffraction results. After alloying with Pb, two Bi-O distances are still observed in the semiconducting alloys ({ital x}=0.75 and 0.50) as well as in the metallic and superconducting phase ({ital x}=0.25). In all the alloys, the two Bi-O distances and their separations decrease somewhat with increasing Pb concentration. The weighted average of the Bi-O and Pb-O distances is consistent with half the pseudocubic cell edge ({ital V}{sup 1/3}) determined from diffraction. The different Bi-O bond lengths are accompanied by charge-density fluctuations which may enhance local, breathing-type phonon modes and thereby increase the coupling between electron and phonon states. For the metallic and superconducting phase, these fluctuations are consistent with a local charge-density-wave picture and the presence of a pseudogap. These results may have implications for the superconductivity, with a relatively high {ital T}{sub {ital c}}, in these oxides.

• OSTI ID: 5294189
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 44:13; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION SPECTRA
ALKALINE EARTH METAL COMPLEXES
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
AMINES
AMMONIUM COMPOUNDS
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BARIUM COMPOUNDS
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BOND LENGTHS
CHALCOGENIDES
COMPLEXES
CRYSTAL STRUCTURE
DIMENSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
LEAD COMPOUNDS
LEAD OXIDES
LENGTH
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PEROVSKITES
PHYSICAL PROPERTIES
QUATERNARY COMPOUNDS
RADIATIONS
SPECTRA
SUPERCONDUCTIVITY
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
X RADIATION