Optimization of YBCO surfaces for tunnel junctions

Conference · Wed Mar 01 04:00:00 EST 1989 · IEEE Trans. Magn.; (United States)

OSTI ID:6091456

Gavaler, J R; Braginski, A I; Forrester, M G; Talvacchio, J; Greggi, J

The authors have established that in YBa/sub 2/Cu/sub 3/O/sub 7/ films, prepared by annealing amorphous oxide deposits, Ba segregation in the amorphous phase and YBCO decomposition after crystallization are the major causes of surface degradation. They have grown films, by entirely in-situ processing, in which these effects are minimized. These films were epitaxially grown on (100) SrTiO/sub 3/ substrates with the a-axis normal to the film plane. Both structural and chemical analyses indicated that they were homogeneous and have proper stoichiometry up to their surfaces. At 4.2K, contract resistivities below 4 x 10/sup -10/ ohm-cm/sup 2/ were obtained with gold overlayers. Junctions have been formed by depositing thin Au proximity layers over the YBCO films followed by MgO barriers and Nb counterelectrodes. In some of the junctions weak-link shorts were observed providing unambiguous evidence that the growth procedures used can produce films that are superconducting up to their surfaces.

• Research Organization: Westinghouse R and D Center, Pittsburgh, PA (US)
• OSTI ID: 6091456
• Report Number(s): CONF-880812-
• Conference Information: Journal Name: IEEE Trans. Magn.; (United States) Journal Volume: 25:2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
420201* -- Engineering-- Cryogenic Equipment & Devices
656003 -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
656100 -- Condensed Matter Physics-- Superconductivity
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
ANNEALING
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
CHEMICAL ANALYSIS
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALLIZATION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
EPITAXY
FILMS
GOLD
HEAT TREATMENTS
JUNCTIONS
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
METALS
NIOBIUM
OPTIMIZATION
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
STOICHIOMETRY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTING FILMS
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTIVITY
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES