High-Field Critical Current Properties of (Bi, Pb)2Sr2Ca2Cu3Oy Filaments

Daichi Kobayashi, Tatsunori Okada, Satoshi Awaji

Research output: Contribution to journalArticlepeer-review


To understand the temperature, magnetic field, and angular dependence of the critical current density, <i>J</i><sub>c</sub>(<i>T</i>, <i>B</i>, <i></i>), of (Bi, Pb)<sub>2</sub>Sr<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>y</sub> (Bi2223) core composed of commercial Bi2223 tapes, we investigated <i>J</i><sub>c</sub>(<i>T</i>, <i>B</i>, <i></i>) of a bundle of Bi2223 filaments extracted from Ag-sheathed Bi2223 tapes under broad (<i>T</i>, <i>B</i>, <i></i>) conditions. We found that flux pinning curves for <i>B</i>||<i>c</i> (<i></i> = 0) exhibit a temperature-scaling relation at high <i>T</i> (5077.3 K) but not at low <i>T</i> (30-40 K). We also found that <i>J</i><sub>c</sub>(<i></i>) exhibits a broad peak in the <i>B</i>||<i>ab</i> (<i></i> = 90) direction and attributed it to the broadening of a sharp peak due to the intrinsic pin caused by a <i>c</i>-axis misalignment. We plotted <i>J</i><sub>c</sub>(<i>T</i>, <i>B</i>, <i></i>) as a function of the tape normal component of the magnetic field considering the <i>c</i>-axis misalignment, and it agrees well with the measured <i>J</i><sub>c</sub>(<i>T</i>, <i>B</i>, 0). This indicates that the intrinsic pinning is strong in Bi2223 and <i>J</i><sub>c</sub>(<i></i>) of Bi2223 is dominated by the flux pinning for the <i>B</i>||<i>c</i> component. Based on these findings, we succeeded in reproducing <i>J</i><sub>c</sub>(<i>T</i>, <i>B</i>, <i></i>) at 50-77.3 K by a model taking account of the <i>T</i>-scaling law, <i>c</i>-axis misalignment, and intrinsic pinning.

Original languageEnglish
JournalIEEE Transactions on Applied Superconductivity
Publication statusAccepted/In press - 2021


  • Bi2223 filament
  • Coils
  • critical current
  • Critical current density (superconductivity)
  • intrinsic pin
  • ir-reversibility field
  • Magnetic field measurement
  • Magnetic fields
  • Pins
  • Superconducting magnets
  • Temperature dependence

ASJC Scopus subject areas

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


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