Temperature dependency of levitation force and its relaxation in HTS

T. Suzuki, E. Ito, T. Sakai, S. Koga, Masato Murakami, K. Nagashima, Y. Miyazaki, H. Seino, Naomichi Sakai, I. Hirabayashi, K. Sawa

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

High-temperature superconductors (HTS) have high potential for various engineering applications such as a superconducting flywheel energy storage system. The attractive feature of the superconducting magnetic bearings in the energy storage system is a reduction in the rotational loss. In this study, we studied the feasibility of a superconducting magnet to support bulk superconductors in magnetic bearings with the aim of increasing the stored energy. The superconducting magnet has a room temperature bore of 100 mm with the maximum magnetic field of 3.5 T. In addition, we used a GM freezer (10 K in the lowest attainment temperature), which can control the temperature of the bulk superconductors. The used bulk samples were Y-Ba-Cu-O and Sm-Ba-Cu-O 46 mm in diameter and 15 mm in thickness fabricated with a top-seeded melt-growth process. We have studied the effects of the temperature and magnetic field on the levitation force and its time relaxation. The levitation forces were measured by applying the magnetic fields of 0-2 T at 10-77.3 K. It was found that the levitation force increased with lowering temperature in both samples. The time relaxation of the levitation force was also reduced with lowering temperature. Sm-Ba-Cu-O exhibited better performance in the levitation force and its time relaxation in a high temperature and high-field region.

Original languageEnglish
Pages (from-to)3020-3023
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Volume17
Issue number2
DOIs
Publication statusPublished - 2007 Jun

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High temperature superconductors
levitation
high temperature superconductors
magnetic bearings
Relaxation time
relaxation time
superconducting magnets
energy storage
Magnetic bearings
Superconducting magnets
Magnetic fields
Temperature
Energy storage
Superconducting materials
temperature
magnetic fields
flywheels
Flywheels
temperature distribution
engineering

Keywords

  • Bulk superconductor
  • Flux creep
  • Levitation
  • Sm-Ba-Cu-O
  • Y-Ba-Cu-O

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Physics and Astronomy (miscellaneous)

Cite this

Temperature dependency of levitation force and its relaxation in HTS. / Suzuki, T.; Ito, E.; Sakai, T.; Koga, S.; Murakami, Masato; Nagashima, K.; Miyazaki, Y.; Seino, H.; Sakai, Naomichi; Hirabayashi, I.; Sawa, K.

In: IEEE Transactions on Applied Superconductivity, Vol. 17, No. 2, 06.2007, p. 3020-3023.

Research output: Contribution to journalArticle

Suzuki, T, Ito, E, Sakai, T, Koga, S, Murakami, M, Nagashima, K, Miyazaki, Y, Seino, H, Sakai, N, Hirabayashi, I & Sawa, K 2007, 'Temperature dependency of levitation force and its relaxation in HTS', IEEE Transactions on Applied Superconductivity, vol. 17, no. 2, pp. 3020-3023. https://doi.org/10.1109/TASC.2007.899403
Suzuki, T. ; Ito, E. ; Sakai, T. ; Koga, S. ; Murakami, Masato ; Nagashima, K. ; Miyazaki, Y. ; Seino, H. ; Sakai, Naomichi ; Hirabayashi, I. ; Sawa, K. / Temperature dependency of levitation force and its relaxation in HTS. In: IEEE Transactions on Applied Superconductivity. 2007 ; Vol. 17, No. 2. pp. 3020-3023.
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