Influence of oxide layers on the microwave surface resistance of superconducting niobium
Thesis/Dissertation
·
OSTI ID:6595035
The author measured the influence of oxide layers grown at room temperature on the microwave surface resistance of superconducting niobium by comparing the quality factors of oxidized and unoxidized cavities. He also investigated the microwave and surface properties that are altered when oxide layers are heated to temperatures near 300/sup 0/C. Auger spectroscopy was used to determine a procedure for producing clean oxygen-free surfaces by ultra-high-vacuum firing the niobium at 1100-1400/sup 0/C. A special vacuum furnace was then constructed so that the 8.6-Ghz niobium cavities could be fired at these temperatures and then taken to a cryostat for testing without any exposure to air. These cavities exhibited residual resistances of 6-12 nOMEGA. Exposure of niobium to oxygen at room temperature is known to create a approx. 15A thick layer consisting mostly of Nb/sub 2/O/sub 5/. This layer changed the temperature-dependent BCS resistance by less than 2%, and changed the low-temperature residual resistance by less than 1.5 nOMEGA.
- Research Organization:
- Cornell Univ., Ithaca, NY (USA)
- OSTI ID:
- 6595035
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
360104 -- Metals & Alloys-- Physical Properties
420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHEMICAL REACTIONS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FILMS
IMPURITIES
METALS
NIOBIUM
OXIDATION
PHYSICAL PROPERTIES
SUPERCONDUCTING FILMS
SURFACES
TRANSITION ELEMENTS
360104 -- Metals & Alloys-- Physical Properties
420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHEMICAL REACTIONS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FILMS
IMPURITIES
METALS
NIOBIUM
OXIDATION
PHYSICAL PROPERTIES
SUPERCONDUCTING FILMS
SURFACES
TRANSITION ELEMENTS