Critical current and upper critical field of multifilament Nb/sub 3-x/Ta/sub x/Sn superconductor
Superconductive wires containing 78 filaments of Nb/sub 3-x/Ta/sub x/Sn for 4--16 at. % Ta were produced using the external bronze process to yield a composite with an overall composition 21.4 wt. % Nb--Ta, 64.9 wt. % Cu, and 13.6 wt. % Sn. Reaction periods of 20 to 260 h at temperatures from 650 to 735 /sup 0/C were used. Critical-current densities over the entire wire cross section were 5 x 10/sup 4/ A/cm/sup 2/ at 14 T and 1 x 10/sup 4/ at 19.7 T, the measured H/sub c/2 was 27 T at 4.2 K for wires with 8 ..mu..m filaments containing approximately 4 at. % Ta. Single filament wires using a 13 wt. % bronze matrix were fabricated to determine the effect of Ta on reaction kinetics. The A15 layer thickness was approximately proportional to the square root of the reaction time and independent of tantalum concentration. The critical-current densities are discussed in terms of A15 grain structure, stoichiometry, filament uniformity, and H/sub c/2 enhancement.
- Research Organization:
- Intermagnetics General Corporation, Charles Industrial Park, Guilderland, New York 12084
- OSTI ID:
- 7057465
- Journal Information:
- J. Appl. Phys.; (United States), Vol. 56:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COPPER ALLOYS
CRITICAL CURRENT
CRITICAL FIELD
CURRENT DENSITY
FABRICATION
NIOBIUM ALLOYS
SUPERCONDUCTING WIRES
TANTALUM ALLOYS
TIN ALLOYS
HIGH TEMPERATURE
LAYERS
REACTION KINETICS
THICKNESS
ALLOYS
CURRENTS
DIMENSIONS
ELECTRIC CURRENTS
KINETICS
MAGNETIC FIELDS
WIRES
360104* - Metals & Alloys- Physical Properties
656102 - Solid State Physics- Superconductivity- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena- (-1987)