Effect of oxygen pressure on the synthesis of YBa sub 2 Cu sub 3 O sub 7 minus x thin films by post-deposition annealing
- Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6057 (USA)
The effect of ambient oxygen pressure on the synthesis of epitaxial YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} films on (100) SrTiO{sub 3} substrates by post-deposition annealing of amorphous precursor films was studied for oxygen partial pressures {ital p}{sub O{sub 2}} between 1.0 and 8.0{times}10{sup {minus}5} atm and annealing temperatures between 890 and 650 {degree}C. A {ital p}{sub O{sub 2}}{minus}1/{ital T} diagram containing recent literature data regarding YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} oxygen stoichiometry, phase stability, and liquid-phase formation was compiled to provide guidance for the selection and interpretation of annealing conditions. The results evidence a strong dependency of growth properties on the oxygen pressure with enhanced {ital c}-oriented epitaxy at lower {ital p}{sub O{sub 2}} values. A particularly interesting result is the formation of predominantly {ital c}-oriented films at 740 {degree}C and {ital p}{sub O{sub 2}}=2.6{times}10{sup {minus}4} atm (0.2 Torr). Similar to YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} films produced by {ital in} {ital situ} laser ablation at the same temperature and oxygen pressure, the films exhibited low ion channeling yields ({chi}{sub min}{lt}0.1) and a dense (smooth) surface morphology, while critical currents at 77 K were well in excess of 1 MA/cm{sup 2}. From the observed systematic variation of structural film properties with synthesis conditions, annealing lines were derived indicating ({ital T}-{ital p}{sub O{sub 2}}) combinations for either {ital c}- or {ital a}-oriented epitaxial growth. A comparison is made between these lines and synthesis conditions for {ital in} {ital situ} film growth as compiled recently by Hammond and Bormann (Physica C {bold 162}--{bold 169}, 703 (1989)).
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5561271
- Journal Information:
- Journal of Applied Physics; (USA), Vol. 69:9; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BARIUM OXIDES
CRITICAL CURRENT
SYNTHESIS
COPPER OXIDES
YTTRIUM OXIDES
ANNEALING
EPITAXY
FILMS
LOW TEMPERATURE
MORPHOLOGY
OXYGEN
PARTIAL PRESSURE
SURFACES
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
CURRENTS
ELECTRIC CURRENTS
ELEMENTS
HEAT TREATMENTS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
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