Occurrence of Flux Jumps in MgB2 Bulk Magnets during Pulse-Field Magnetization

N. Sakai, T. Oka, K. Yamanaka, L. Dadiel, H. Oki, J. Ogawa, S. Fukui, J. Scheiter, W. Häßler, K. Yokoyama, J. Noudem, M. Miryala, M. Murakami

Research output: Contribution to journalConference article

Abstract

The magnetic flux capturing of MgB2 bulk magnets made by spark plasma sintering process has been precisely investigated to clarify the mechanism of flux motions during the pulse-field magnetization processes. The field trapping ratio B T/B P was evaluated as a key parameter of field trapping ability which strongly relates to the heat generation due to the rapid flux motion in the samples. The time dependence of magnetic flux density revealed the actual flux motion which penetrated the samples. The trapped fields B T and field trapping ratios B T/B P of various samples were classified into three regions of 'no flux flow', 'fast flux flow' and 'flux jump' according to the generation of heat and its propagation. A flux jump was observed late at 280 ms from the beginning of PFM process, while the field penetration B P showed its peak at 10 ms. Considering the heat propagation speed, the long-delayed flux jump should be attributed to the macroscopic barriers against the heat propagation to the surface centre of bulk magnet.

Original languageEnglish
Article number012024
JournalJournal of Physics: Conference Series
Volume1559
Issue number1
DOIs
Publication statusPublished - 2020 Jun 19
Event14th European Conference on Applied Superconductivity, EUCAS 2019 - Glasgow, United Kingdom
Duration: 2019 Sep 12019 Sep 5

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Sakai, N., Oka, T., Yamanaka, K., Dadiel, L., Oki, H., Ogawa, J., Fukui, S., Scheiter, J., Häßler, W., Yokoyama, K., Noudem, J., Miryala, M., & Murakami, M. (2020). Occurrence of Flux Jumps in MgB2 Bulk Magnets during Pulse-Field Magnetization. Journal of Physics: Conference Series, 1559(1), [012024]. https://doi.org/10.1088/1742-6596/1559/1/012024