CUED Publications database

Demagnetization study of pulse-field magnetized bulk superconductors

Srpcic, J and Zhou, D and Huang, KY and Shi, Y and Dennis, A and Ainslie, MD and Campbell, AM and Bause, R and Boll, M and Filipenko, M and Cardwell, DA and Durrell, JH (2018) Demagnetization study of pulse-field magnetized bulk superconductors. IEEE Transactions on Applied Superconductivity, 28. ISSN 1051-8223

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GdBa2Cu3O7-δ bulk superconductors are a route to higher magnetic fields in rotating machines. Here, we examine the resistance of pulse-field magnetized bulks to the demagnetization fields they may experience in such a system. The bulks were magnetized at 77 K, after which several thousand cycles of AC field were applied. Subsequently, the decay of the trapped field was characterized. We found that the decay per cycle decreases with frequency and is, normalized to the initial trapped field, largest at the edge of the bulk. At 77 K, the reduction in trapped field proved significant (25% in the center for 150 mT (peak) AC field at 6 Hz), however, reducing below 1% when lowering the temperature to 60 K. We explain this observation as being due to increased flux pinning strength at low temperatures. When applying an AC field, we found a temperature rise that increased with applied field amplitude and frequency. However, when applying an AC field of amplitude 45 mT with a frequency of 48 Hz, we found an increase of the bulk temperature of only 100 mK. Therefore, we conclude that the temperature rise within the analyzed AC field frequency and amplitude range does not contribute significantly to the decay of trapped field.

Item Type: Article
Divisions: Div C > Materials Engineering
Div C > Engineering Design
Depositing User: Cron Job
Date Deposited: 12 Feb 2018 20:05
Last Modified: 31 Aug 2021 07:21
DOI: 10.1109/TASC.2018.2808400