Fabrication of small superconducting coils using (Ba,A)Fe2As2(A: Na, K) round wires with large critical current densities

Sunseng Pyon, Haruto Mori, Tsuyoshi Tamegai, Satoshi Awaji, Hijiri Kito, Shigeyuki Ishida, Yoshiyuki Yoshida, Hideki Kajitani, Norikiyo Koizumi

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


We report the fabrication of small (Ba,A)Fe2As2 (A: Na, K) coils using 10 m-class long round wires, fabricated by the powder-in-tube method. Coils are sintered using the hot-isostatic-press technique after glass-fiber insulations are installed. Critical current (I c) of the whole coil using (Ba,Na)Fe2As2 and (Ba,K)Fe2As2 are 60 A and 66 A under the self-field, and the generated magnetic fields at the center of the coil reach 2.6 kOe and 2.5 kOe, respectively. Furthermore, the largest transport critical current density (J c) and I c in (Ba,Na)Fe2As2 wires picked up from the coil reach 54 kA cm-2 and 51.8 A at T = 4.2 K under a magnetic field of 100 kOe, respectively. This value exceeds transport J c of all previous iron-based superconducting round wires. Texturing of grains in the core of the wire due to the improvement of the wire drawing process plays a key role for the enhancement of J c.

Original languageEnglish
Article number105008
JournalSuperconductor Science and Technology
Issue number10
Publication statusPublished - 2021 Oct


  • (Ba,K)FeAs
  • (Ba,Na)FeAs
  • HIP round wires
  • critical current
  • critical current density
  • iron-based superconductor
  • superconducting coil

ASJC Scopus subject areas

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


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