Progress in Superconductivity

The Korean Superconductivity Society (한국초전도학회)
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Magnetic Pinning Properties and Flux Jumps in Superconducting $MgB_2$

  • Yoon, W.S. (Department of Physics, Kyungpook National University) ;
  • Lee, Eui-Wan (Department of Physics, Kyungpook National University) ;
  • Kim, C.J. (Nuclear Nanomaterial Development Laboratory, Korea Atomic Energy Research Institute(KAERI)) ;
  • Kim, B.G. (HANARO Utilization Technology Development Center, Korea Atomic Energy Research Institute(KAERI)) ;
  • Ri, H.C. (Department of Physics, Kyungpook National University)
  • Published : 2007.10.31
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Abstract

Magnetization studies have been carried out on $MgB_2$ polycrystalline samples in the temperature range of 5 - 44 K and in the magnetic field up to 7 Tesla. The critical current density was calculated from hysteresis loops using the Bean's critical state model, and the highest value of $J_c$ at 20 K was $2.7{\times}10^5\;A/cm^2$ at 2 Tesla. The hysteresis loops were carefully examined to determine the temperature and magnetic field range where flux jumps appeared. The first jump occurred typically at 1 Tesla. Due to the strong pinning, we observed the presence of flux jump below H = 1 Tesla at temperature below 30 K.

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