Fe site occupancy and superconductivity in Y sub 1-z Ca sub z Ba sub z (Cu sub 1-x Fe sub x ) sub 3 O sub 6+y
X-ray diffraction and {sup 57}Fe Moessbauer spectroscopy studies show that partial substitution of Ca for Y in Y{sub 1-z}Ca{sub z}Ba{sub 2}(Cu{sub 1-x}Fe{sub x}){sub 3}O{sub 6+y} (0.05 {le} z {le} 0.15,0.003 {le} x {le} 0.20) result in increased Fe solubility and a larger percentage of Fe occupancy of the Cu(2) plane site (prepared conventionally). Materials with z {gt} 0.00 have a slightly depressed superconducting transition onset temperature {Tc} relative to the z = 0.00 compounds. It is also shown that Fe occupancy of the Cu(2) site in Y{sub 1-z}Ca{sub z}Ba{sub 2}(Cu{sub 1-x}Fe{sub x}){sub 3}O{sub 6+y} can be substantially increased when these materials are treated at high temperatures in inert atmospheres followed by oxygenation at low temperatures. {Tc} decreases more rapidly in these latter materials compared to the conventionally prepared ones. Implications concerning ordered Fe cluster formation and superconducting pair breaking in the Cu(2) site are drawn. 7 refs., 4 tabs.
- Research Organization:
- Los Alamos National Lab., NM (USA)
- Sponsoring Organization:
- DOE/AD
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6899741
- Report Number(s):
- LA-UR-90-2671; CONF-901004--4; ON: DE90016614
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
656100* -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CALCIUM COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
DIFFRACTION
GAMMA SPECTROMETERS
HIGH-TC SUPERCONDUCTORS
IRON COMPOUNDS
IRON OXIDES
MEASURING INSTRUMENTS
MOESSBAUER SPECTROMETERS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SCATTERING
SPECTROMETERS
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
X-RAY DIFFRACTION
YTTRIUM COMPOUNDS