Doping mechanism in Bi(Pb)-Sr-Ca-Cu-O superconductors

Journal Article · Wed Nov 15 04:00:00 EST 1989 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.343806· OSTI ID:5371748

Ramesh, R; Hegde, M S; Chang, C C; Tarascon, J M ^[1]; Green, S M; Luo, H L ^[2]

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1. Bellcore, Red Bank, New Jersey 07701 (USA)
2. Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (USA)

A model that explains the doping mechanism in Bi(Pb)-Sr-Ca-Cu-O superconductor is presented. X-ray microanalysis reveals that the excess oxygen can be accounted for by the exact stoichiometry of the {ital n}=2 and 3 phases. We show that the presence of excess oxygen associated with the structural modulation in the compound is not sufficient to explain the hole concentration required by the transition temperature observed. Using a bond valence argument, we show that the effective valence of the Bi ion in the BiO bilayers is smaller than the expected value of +3, due to the incomplete oxygen coordination around the Bi ion. The model qualitatively explains the observations of lowering of {ital T}{sub {ital c}} with Er (or Tm) doping or oxygen annealing. The role of Pb addition is suggested to be one of altering the thermodynamics and kinetics of formation of the {ital n}=3 phase.

• OSTI ID: 5371748
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 66:10; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
CHEMICAL BONDS
CHEMICAL REACTIONS
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL DOPING
ELECTROMAGNETIC RADIATION
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
ELEMENTS
IONIZING RADIATIONS
LEAD
METALS
MICROSCOPY
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
RADIATIONS
SPECTROSCOPY
STOICHIOMETRY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
TRANSMISSION ELECTRON MICROSCOPY
VALENCE
X RADIATION