Trapped field characteristics of Y-Ba-Cu-O bulk in time-varying external magnetic field

Citation
T. Ohyama et al., Trapped field characteristics of Y-Ba-Cu-O bulk in time-varying external magnetic field, IEEE APPL S, 11(1), 2001, pp. 1988-1991
Citations number
4
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
ISSN journal
1051-8223 → ACNP
Volume
11
Issue
1
Year of publication
2001
Part
2
Pages
1988 - 1991
Database
ISI
SICI code
1051-8223(200103)11:1<1988:TFCOYB>2.0.ZU;2-T
Abstract
The trapped field characteristics of disk-shaped YBCO bulk exposed to exter nal AC magnetic field are investigated experimentally, The magnetic flux de nsity an the top surface of the disk defined as "trapped flux" in this pape r, was measured in both short and long tel ms as functions of amplitude and frequency of the AC external magnetic field. The observed trapped flux att enuation was obviously different from that of flux creep, i.e,, with no ext ernal magnetic field; this Implies that the trapped flux density within the YBCO dish is reduced by a temperature rise due to AC loss, The abrupt atte nuation of trapped flux density in the first several cycles was observed at frequencies of 0.1 and 1 Hz, while not observed at 10 Hz The attenuation r ate after seven minutes of applying AC magnetic field, however, became almo st the same regardless of frequency. The trapped Bur attenuation in one cyc le of, AC magnetic field decreases with the frequency and increases with th e amplitude of AC magnetic field. These results imply that tile characteris tic of trapped pus is closely related to AC loss, especially the hysteresis -loss, and the AC loss depends on the frequency and the amplitude of the AC external magnetic field. at can he considered that transient electromagnet ic behavior within HTS bulk, especially supercurrent distribution, is a key factor. of the relationship between the trapped flux attenuation and the A C loss.