Magnetisation and instability in melt-textured YBa2Cu3O7 at low temperature and high fields up to 23 T

G. C. Han, K. Watanabe, S. Awaji, N. Kobayashi, K. Kimura

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12 Citations (Scopus)


Magnetisation loops of QMG-processed bulk YBa2Cu3O7 were measured at 4.2 K in fields up to 23 T using a new vibrating sample magnetometer (VSM) combined with a hybrid magnet. Jc characteristics were derived from the measured magnetisation curves using the Bean critical state model. Flux jumps, which were often observed in magnetisation measurements for high-Jc bulk samples at low temperature, were not observed in these measurements. Magnetisation loops measured by conventional VSM and by SQUID for the same sample show that flux jumps appear even at a lower field sweep rate. The magnetic instability depends on the measuring conditions. These results suggest that the flux jumps may be induced not only by poor heat conductivity from a sample to its surroundings in SQUID, but also by the larger vibration amplitude in conventional VSM. Using conventional VSM the dependence of the flux jump on field sweep rates was also measured from 15 to 0.75 T/min. The field at first flux jump increases with decreasing sweep rate.

Original languageEnglish
Pages (from-to)33-38
Number of pages6
JournalPhysica C: Superconductivity and its applications
Issue number1-2
Publication statusPublished - 1997 Jan 15


  • 74.60.G
  • 74.60.J

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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