Controlled grain boundary structures in superconductors. Final report 1 Jan 77-31 Dec 81
Technical Report
·
OSTI ID:6693986
Theoretical work supported by this grant has lead to the concept of the specific pinning force Q and the development of new methods to sum elementary interaction forces to find Q. Pinning due to changes in transition temperature or thermodynamic critical field in thin layers (e.g., a grain boundary), is greatly reduced due to the proximity effect and the stress field interaction due to the dislocations in the grain boundary has been shown to be negligible. The crystalline anisotropy (CA) and electron scattering (ES) interactions have been computed for the first time for an arbitrary boundary. Experiments on niobium bicrystals, polycrystalline niobium thin foils doped with oxygen, lead-bismuth alloy thin films and lead-bismuth alloy films in which either lead or thallium has been allowed to diffuse down the grain boundaries and out into the grains provide evidence that confirms the predictions of the theory. These results suggest that further improvements in grain boundary pinning in the A-15 compounds, which are relatively high purity, are possible by decreasing their impurity content if that can be accomplished without decreasing their thermodynamic critical field or transition temperature.
- Research Organization:
- Cornell Univ., Ithaca, NY (USA). Dept. of Materials Science and Engineering
- OSTI ID:
- 6693986
- Report Number(s):
- AD-A-114243/9
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
360104 -- Metals & Alloys-- Physical Properties
656102* -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
CONTROL
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTALS
DIMENSIONS
DISLOCATIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FOILS
GRAIN BOUNDARIES
IMPURITIES
LINE DEFECTS
METALS
MICROSTRUCTURE
NIOBIUM
NONMETALS
OXYGEN
PHYSICAL PROPERTIES
POLYCRYSTALS
SUPERCONDUCTIVITY
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
THICKNESS
TRANSITION ELEMENTS
TRANSITION TEMPERATURE
360104 -- Metals & Alloys-- Physical Properties
656102* -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
CONTROL
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTALS
DIMENSIONS
DISLOCATIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FOILS
GRAIN BOUNDARIES
IMPURITIES
LINE DEFECTS
METALS
MICROSTRUCTURE
NIOBIUM
NONMETALS
OXYGEN
PHYSICAL PROPERTIES
POLYCRYSTALS
SUPERCONDUCTIVITY
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
THICKNESS
TRANSITION ELEMENTS
TRANSITION TEMPERATURE