1. Demagnetization Study of Pulse-Field Magnetized Bulk Superconductors
- Author
-
Kai Yuan Danny Huang, A R Dennis, Difan Zhou, David A. Cardwell, Mykhaylo Filipenko, Roman Bause, Mark D. Ainslie, A.M. Campbell, Jan Srpcic, John H. Durrell, Martin Boll, Yunhua Shi, Srpcic, J [0000-0001-8195-4188], Zhou, D [0000-0001-9889-8872], Ainslie, MD [0000-0003-0466-3680], Campbell, AM [0000-0002-4087-3581], Boll, M [0000-0002-9778-4280], Durrell, JH [0000-0003-0712-3102], and Apollo - University of Cambridge Repository
- Subjects
Superconductivity ,Range (particle radiation) ,Materials science ,Flux pinning ,Condensed matter physics ,Field (physics) ,Demagnetizing field ,Bulk temperature ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,high-temperature superconductors ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Magnetic field ,Amplitude ,trapped field magnets ,0103 physical sciences ,trapped field attenuation ,superconducting magnets ,Electrical and Electronic Engineering ,010306 general physics ,0210 nano-technology - Abstract
GdBa 2 Cu 3 O 7-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.
- Published
- 2018