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Weakening of Flux-Pinning Strength for High Tc Superconductors in an Alternating Magnetic Field

Published online by Cambridge University Press:  26 February 2011

Q. Y. Chen
Q. Y. Chen*
Affiliation:
Texas Center for Superconductivity, University of Houston, Houston, Texas 77024–5932
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Abstract

The flux-pinning forces in high temperature superconductors were found to be weakened in an ac field as the applied field strength or the frequency increases. In the weakly pinned regime, flux dynamics could be described widi the concept of magnetic diffusion. Flux-motion-induced finite resistivity could lead to significant skin-effect which was reflected in the ac screening effectiveness. The frequency dependence of the relative local field within a superconducting hollow cylinder were used to deduce the flux-motion resistivity (ρ). For superconducting YB2Cu3O7−x compounds at 77K it was found that ρ≈ 1μΩ-cm. The corresponding magnetic diffusion coefficient was ≈224 cm2/s. At 750 Hz the skin depth is around 1.54 mm as compared with the 2-mra sample wall thickness.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 275: Symposium S – Layered Superconductors: Fabrication, Properties and Applications , 1992 , 777
Copyright
Copyright © Materials Research Society 1992

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References

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