Strong enhancement of high-field critical current properties and irreversibility field of MgB2 superconducting wires by coronene active carbon source addition via the new B powder carbon-coating method

Shu Jun Ye, Akiyoshi Matsumoto, Yun Chao Zhang, Hiroaki Kumakura

Research output: Contribution to journalArticlepeer-review

Abstract

We report an effective carbon-containing additive, coronene (C 24H12), for MgB2 superconducting wires. We used B powder coated with C24H12 to fabricate MgB2 wires using the powder-in-tube (PIT) and internal Mg diffusion (IMD) processes. The in-field critical current properties are strongly enhanced for both PIT- and IMD-processed MgB2 wires. For PIT MgB2 wires, a critical current density (Jc) value of 1.8×104 A cm -2 is obtained at 4.2 K and 10 T. For IMD MgB2 wires, we obtained a Jc of 1.07×105 A cm-2 and an engineering Jc (Je) of 1.12×104 A cm -2 at 4.2 K and 10 T. These Jc and Je values are similar to the highest values reported for MgB2 wires thus far. Furthermore, the irreversibility field, Birr, determined with a current density criterion of 100 A cm-2, is strongly enhanced to 25 T at 4.2 K, which is also the highest value reported for MgB2 superconducting wires thus far. Coronene is an active carbon source for MgB 2 superconducting wires because (1) coronene has a high carbon content (96 wt%) with a small amount of hydrogen (impurity), (2) the decomposition temperature for coronene is near the reaction temperature between Mg and B, and (3) uniform dispersion of coronene on the B surface can be obtained due to the melting point of coronene being lower than the decomposition temperature. Carbon substitution for B caused by the coronene active carbon source is mainly responsible for the high field critical current properties and the high Birr obtained in this work.

Original languageEnglish
Article number085012
JournalSuperconductor Science and Technology
Volume27
Issue number8
DOIs
Publication statusPublished - 2014 Aug 1
Externally publishedYes

Keywords

  • carbon-coating process
  • coronene
  • critical current density
  • irreversibility field

ASJC Scopus subject areas

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

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