Magnetic impurity scattering in in situ superconductors

Technical Report · Sat Jan 01 04:00:00 EST 1983

OSTI ID:6810684

Finnemore, D K; Yang, H C; Kogan, V G; Miller, S L

Measurements of ac losses for in situ prepared superconducting composites consistently show loss values higher than those observed for bronze process materials. To get the measured ac loss one needs an effective filament size in the range of 20 to 50 ..mu..m. Our goal in this work is to understand quantitatively the origin of this coupling between filaments and to develop methods for contolling it. To reduce the ac losses it is desirable to reduce the cross linking of filaments and the proximity coupling through the Cu. This should not reduce J/sub c/ because in all cases J/sub c/ is controlled by pinning of the flux line lattice by either grian boundaries or superconductor-Cu boundaries. In fact, J/sub c/ vs H curves are essentially the same as for continuous filament materials. There is no evidence that a breakdown of the proximity coupling in the Cu controls J/sub c/ and there seems to be more than adequate filament-filament coupling. Therefore the goal is to reduce this filament-filament coupling, both cross joining and proximity coupling. The first step in this is to control proximity coupling by the introduction of magnetic impurities into the normal metal barrier. Presented here are the results of a study of the model system Pb-(AgMn)-Pb to understand all of the basic physics involved and to learn quantitatively the effects of magnetic impurity scattering in the N layer. Because both magnetic and non-magnetic scattering will be important in the Cu-Nb/sub 3/Sn systems we add both Mn and Al to the Ag to determine the effects of both the magnetic scattering rate (pi/sub s//sup -1/) and non-magnetic scattering rate (pi/sub N//sup -1/).

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6810684
• Report Number(s): IS-M-466; CONF-830841-35; ON: DE84012835
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AC LOSSES
ALLOYS
COMPOSITE MATERIALS
COUPLING
CRITICAL CURRENT
CRITICAL TEMPERATURE
CURRENTS
DATA
ELECTRIC CURRENTS
ELEMENTS
ENERGY LOSSES
EXPERIMENTAL DATA
FABRICATION
IMPURITIES
INFORMATION
LEAD
LOSSES
MANGANESE ALLOYS
MATERIALS
METALS
NUMERICAL DATA
PHYSICAL PROPERTIES
PROXIMITY EFFECT
SILVER ALLOYS
SUPERCONDUCTING COMPOSITES
SUPERCONDUCTING WIRES
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
WIRES