Fabrication, characterization, and theoretical analysis of high- T sub c Y-Ba-Cu-O superconducting films prepared by a chemical sol gel method

Journal Article · Thu Aug 01 04:00:00 EDT 1991 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.349521· OSTI ID:5684022

Hussain, A A; Sayer, M ^[1]

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1. Department of Physics, Queen's University, Kingston K7L3N6, Canada (CA)

Thin films of Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} have been produced on MgO substrates by a chemical sol gel method. X-ray diffraction data indicate that the annealed films have the characteristic orthorhombic structure with lattice constants which are nearly the same as the values reported for the bulk specimen of Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}}. Auger electron spectroscopy depth profiling measurements indicate that the films are uniform in thickness and composition. Measurements of electrical resistance of films 1--4.7 {mu}m in thickness have been carried out between 12 and 300 K using a standard four-probe geometry. The films are superconducting with an onset temperature around 95 K and a full transition temperature as high as 79.5 K, and a critical current density of 2700 A/cm{sup 2} at 20 K. A theoretical analysis of the critical current density in Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} as a function of temperature has been made in order to determine the characteristics of the junctions between the superconducting grains. Theoretical models which describe the dependence of the critical current density on temperature have been presented and agreement has been found between these models and experimental values for sol gel films. The critical transport current has a temperature dependence which is characteristic of superconductor-normal metal-superconductor (S-N-S) type junctions. The magnitude of the resistance and thickness of the junctions has been determined from the theoretical models. Information regarding calculation of the oxygen content in Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} films is also presented.

• OSTI ID: 5684022
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 70:3; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
ANNEALING
AUGER ELECTRON SPECTROSCOPY
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL CURRENT
CURRENTS
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
ELECTRON SPECTROSCOPY
FILMS
HEAT TREATMENTS
HIGH-TC SUPERCONDUCTORS
LOW TEMPERATURE
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MEDIUM TEMPERATURE
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SCATTERING
SOL-GEL PROCESS
SPECTROSCOPY
SUBSTRATES
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
THIN FILMS
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE
X-RAY DIFFRACTION
YTTRIUM COMPOUNDS
YTTRIUM OXIDES