Magnetic shielding properties of high-temperature superconducting tubes subjected to axial fields
| Autor: | Philippe Vanderbemden, Rudi Cloots, Laurent Dusoulier, Benoît Vanderheyden, Michel Dirickx, Samuel Denis, Marcel Ausloos |
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| Rok vydání: | 2007 |
| Předmět: |
Superconductivity
Materials science Field (physics) Condensed matter physics Condensed Matter - Superconductivity Metals and Alloys Shell (structure) FOS: Physical sciences Low frequency Condensed Matter Physics Power law Magnetic field Superconductivity (cond-mat.supr-con) Electromagnetic shielding Materials Chemistry Ceramics and Composites Electrical and Electronic Engineering Spatial dependence |
| Zdroj: | Superconductor Science and Technology. 20:192-201 |
| ISSN: | 1361-6668 0953-2048 |
| Popis: | We have experimentally studied the magnetic shielding properties of a cylindrical shell of BiPbSrCaCuO subjected to low frequency AC axial magnetic fields. The magnetic response has been investigated as a function of the dimensions of the tube, the magnitude of the applied field and the frequency. These results are explained quantitatively by employing the method of Brandt (1998 Phys. Rev. B 58 6506) with a Jc(B) law appropriate for a polycrystalline material. Specifically, we observe that the applied field can sweep into the central region either through the thickness of the shield or through the opening ends, the latter mechanism being suppressed for long tubes. For the first time, we systematically detail the spatial variation of the shielding factor (the ratio of the applied field over the internal magnetic field) along the axis of a high-temperature superconducting tube. The shielding factor is shown to be constant in a region around the centre of the tube, and to decrease as an exponential in the vicinity of the ends. This spatial dependence comes from the competition between two mechanisms of field penetration. The frequency dependence of the shielding factor is also discussed and shown to follow a power law arising from the finite creep exponent n. Comment: 22 pages, 10 figures |
| Databáze: | OpenAIRE |
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