Current density dependence of the activation energy in type II superconductors

Journal Article · Wed Jul 15 04:00:00 EDT 1992 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.351837· OSTI ID:7207210

Sengupta, S; Shi, D; Salem-Sugui, S Jr; Wang, Z; McGinn, P J; DeMoranville, K ^[1]

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1. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

We have conducted magnetic relaxation experiments to calculate the effective activation energy, {ital U}, as a function of critical current density. We have shown that, from the nonlinearity of {ital U}, one can explain the nonlogarithmic decay of magnetization in type II superconductors. The nonlinearity of {ital U} was considered by expanding {ital U} about a current density, {ital J}{sub 0}. The coefficients of expansion were determined experimentally and were used to develop the relationship between {ital U} and {ital J} for both conventional type II superconductors (Nb{sub 3}Sn filamentary) and high-{ital T}{sub {ital c}} superconductors (YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} and Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub {ital y}} single crystals). Both types of superconductor were observed to behave in similar fashion. We have also calculated {ital U}{sub 0} using the standard formulas and the intercepts of the tangent of the {ital U} vs {ital M} curve and have found the results to be comparable.

• DOE Contract Number: FG02-90ER45427
• OSTI ID: 7207210
• Journal Information: Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 72:2; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
665411 -- Basic Superconductivity Studies-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACTIVATION ENERGY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CURRENT DENSITY
ENERGY
HIGH-TC SUPERCONDUCTORS
MAGNETIZATION
NIOBIUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
RELAXATION
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTORS
TIN COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TYPE-II SUPERCONDUCTORS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES