Thermal and magnetic behaviors of a melt-textured superconducting bulk magnet in the zero-field-cooling magnetizing process

Tetsuo Oka, K. Yokoyama, H. Fujishiro, K. Noto

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The heat generation and magnetic field trapping behaviors of the melt-textured single-domain Sm-Ba-Cu-O bulk superconductor have been precisely investigated in the zero-field-cooling magnetizing processes (ZFC). The temperature and magnetic flux density were simultaneously measured in the temperature range of 50-60K. Since the invasion of magnetic flux is suppressed by the superconducting pinning effect, the applied magnetic field is not supplied to the whole of the sample. Therefore, the trapped field distributions consequently exhibit trapezoid shapes. According to the balance of heat generation and draining, the temperature profiles show us distinctive behaviors of magnetic fluxes. Both the temperature and the magnetic flux density kept increasing even after the external magnetic field has stopped growing at 5T. This is attributed to the flux creeping phenomenon which propagates from the periphery to the center portion of the sample like a snow slide. The highest temperature rise due to the flux motion reached 7.5K even when the sample was magnetized at a slow sweeping rate of 5.06 mTs-1. As the temperature profiles were different between the ascending and descending field processes, it is suggested that the magnetic fluxes invade in and diffuse out in different heating manners between the processes. This assists the hypothesis that the time while the moving fluxes heat the sample strongly affects the total amount of heat generation, which acts contrary to the FC case. This behavior implies that the improvements of the heat propagation property of the HTS bulk material by embedding metallic membranes and more powerful/efficient cooling systems must suppress the temperature increases and enhance the field trapping abilities.

Original languageEnglish
Article number065014
JournalSuperconductor Science and Technology
Volume22
Issue number6
DOIs
Publication statusPublished - 2009 Aug 11
Externally publishedYes

Fingerprint

Magnets
magnetic flux
magnets
Magnetic flux
heat generation
Cooling
cooling
Heat generation
temperature profiles
Temperature
flux density
trapping
Magnetic fields
magnetic fields
trapezoids
temperature
cooling systems
snow
drainage
Fluxes

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics
  • Ceramics and Composites
  • Materials Chemistry
  • Metals and Alloys

Cite this

Thermal and magnetic behaviors of a melt-textured superconducting bulk magnet in the zero-field-cooling magnetizing process. / Oka, Tetsuo; Yokoyama, K.; Fujishiro, H.; Noto, K.

In: Superconductor Science and Technology, Vol. 22, No. 6, 065014, 11.08.2009.

Research output: Contribution to journalArticle

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