Structure of the Fe-doped high-temperature superconductors Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub y/ and Bi/sub 2/Sr/sub 2/Ca/sub 1/Cu/sub 2/O/sub y/

Journal Article · Wed Feb 01 00:00:00 EST 1989 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.343058· OSTI ID:6603666

Bremert, O; Michaelsen, C; Krebs, H U

The high-temperature superconductors YBa/sub 2/(Cu/sub 1-//sub x/Fe/sub x/)/sub 3/O/sub y/ and Bi/sub 2/Sr/sub 2/Ca/sub 1/(Cu/sub 1-//sub x/Fe/sub x/)/sub 2/O/sub y/ have been examined by resistivity measurements, x-ray diffraction, and Moessbauer experiments in order to understand the influence of Fe on the structure of the perovskites. The concentration dependence of the Fe substitution and the results of the annealing experiments are consistent with the following model which explains the observed structural changes with Fe composition in YBa/sub 2/Cu/sub 3/O/sub y/. For low Fe content, the Fe atoms mainly substitute on the Cu(I) sites leading only to a slight decrease of T/sub c/, but to an attraction of more oxygen ions, which are introduced into the (001) plane. The Fe ions with five- or sixfold coordination act like local symmetry points inducing the formation of short orthogonal chains crossing at the Fe ions. This leads to the orthorhombic-to-tetragonal transition at an Fe concentration of 2.3%. For higher Fe content, T/sub c/ more rapidly decreases, probably due to a partial substitution of Fe also on the Cu(II) sites of the perovskite until the superconductivity vanishes near 16% Fe. The three occuring Moessbauer doublets are assigned to different (four-, five-, and sixfold) oxygen environments of the Fe ions. Similar environments occur in Bi/sub 2/Sr/sub 2/Ca/sub 1/Cu/sub 2/O/sub y/ with 20% Fe, although it is known that no Cu-O chains exist in this structure.

• Research Organization: Institut f uer Metallphysik, University of Goettingen, Hospitalstrasse 3-7, 3400 Goettingen, Federal Republic of Germany
• OSTI ID: 6603666
• Journal Information: J. Appl. Phys.; (United States), Vol. 65:3
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BARIUM OXIDES
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
MOESSBAUER EFFECT
SUPERCONDUCTIVITY
BISMUTH OXIDES
CALCIUM OXIDES
COPPER OXIDES
STRONTIUM OXIDES
YTTRIUM OXIDES
CRYSTAL DOPING
EXPERIMENTAL DATA
IMPURITIES
IRON
PEROVSKITES
STRONTIUM
TRANSITION TEMPERATURE
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
BARIUM COMPOUNDS
BISMUTH COMPOUNDS
CALCIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
DATA
ELECTRICAL PROPERTIES
ELEMENTS
INFORMATION
METALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
STRONTIUM COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YTTRIUM COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360204 - Ceramics
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656100 - Condensed Matter Physics- Superconductivity