Fabrication of square and round Ag/Bi(2223) wires and their ac loss behaviour
| Autor: | K. Kwasnitza, R. Flukiger, X.D. Su, G. Witz |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Copper oxide
Fabrication Materials science High-temperature superconductivity Field (physics) Superconducting wire Metals and Alloys engineering.material Condensed Matter Physics Square (algebra) Magnetic field law.invention chemistry.chemical_compound chemistry law Materials Chemistry Ceramics and Composites engineering Electrical and Electronic Engineering Composite material Anisotropy |
| Zdroj: | Superconductor Science and Technology. 15:1184-1189 |
| ISSN: | 0953-2048 |
| DOI: | 10.1088/0953-2048/15/8/302 |
| Popis: | Square and round wires have been fabricated by using a combination of two-axial rolling and drawing in order to reduce the effect of field anisotropy and to confirm the decrease of ac losses predicted by calculation. Critical current measurements, as a function of magnetic field angle, confirmed that the symmetrical configuration of filaments inside the wire leads to an almost angle-insensitive behaviour of Jc(B). The Bi(2223) grains in our wires have a higher misalignment angle (around 8°) with respect to flat tapes, due to the particular wire configuration and the use of two-axial rolling. Therefore, the Jc values in our square wire are somewhat lower, 11 kA cm−2 at 77 K and zero field. AC loss measurements showed that the combination of wire geometry and twisting leads to strongly reduced ac losses in square Ag/Bi(2223) wires when compared to flat tapes: the value of 0.53 mW A−1 m−1 was measured, regardless of the field direction. |
| Databáze: | OpenAIRE |
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