Control of the hole concentration in the YBa sub 2 Cu sub 3 O sub 6+ z -type superconductors (Yb,Ca)(Ba,Sr) sub 2 Cu sub 3 O sub 6+ z with low and high Ca contents
- Superconductivity Research Laboratory, International Superconductivity Technology Center, 10-13 Shinonome 1-Chome, Koto-ku, Tokyo 135 (Japan)
(Yb{sub 1{minus}{ital x}}Ca{sub {ital x}}) (Ba{sub 0.8}Sr{sub 0.2}){sub 2}Cu{sub 3}O{sub 6+{ital z}} (0{le}{ital x}{le}0.4) solid solutions of the YBa{sub 2}Cu{sub 3}O{sub 6+{ital z}} ( 1:2:3'') -type structure were successfully synthesized. The solid-solution samples were characterized with respect to the oxygen content, crystal structure, and superconducting properties. The fully oxygenated'' samples with {ital z}{similar to}0.8 were prepared employing postannealing at high oxygen partial pressure atmosphere ({ital P}(O{sub 2})=400 atm). The samples had orthorhombic unit cells and showed bulk superconductivity. The superconducting transition temperatures ({ital T}{sub {ital c}}'s) ranged from 80 to 32 K, depending on the Ca content. Samples with {ital x}=0.1 and 0.3, and various oxygen contents (0.36{le}{ital z}{le}0.89 for {ital x}=0.1 and 0.10{le}{ital z}{le}0.78 for {ital x}=0.3) were prepared by employing quenching and annealing techniques. For (Yb{sub 0.7}Ca{sub 0.3}) (Ba{sub 0.8}Sr{sub 0.2}){sub 2}Cu{sub 3}O{sub 6+{ital z}}, as the oxygen content {ital z} decreased, {ital T}{sub {ital c}} increased from 40 K first, then peaked at 82 K at {ital z}=0.56, and decreased down to 48 K at {ital z}=0.10. The relationship between {ital T}{sub {ital c}} and the hole concentration in the CuO{sub 2} sheet, {ital p}{sub sheet}, was obtained. {ital T}{sub {ital c}} was maximum at {ital p}{sub sheet}=0.18 for both samples with {ital x}=0.1 and 0.3.
- OSTI ID:
- 5481393
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 44:5; ISSN PRBMD; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
ANNEALING
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM
CALCIUM COMPOUNDS
CALCIUM OXIDES
CARRIER DENSITY
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
HEAT TREATMENTS
HIGH-TC SUPERCONDUCTORS
HOLES
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
METALS
MIXTURES
NONMETALS
OPTIMIZATION
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
QUANTITY RATIO
SOLID SOLUTIONS
SOLUTIONS
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TETRAGONAL LATTICES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES