Understanding the route to high critical current density in mechanically alloyed Mg(B1-xCx)2

B. J. Senkowicz, A. Polyanskii, R. J. Mungall, Ye Zhu, J. E. Giencke, P. M. Voyles, C. B. Eom, E. E. Hellstrom, D. C. Larbalestier

Research output: Journal article publicationJournal articleAcademic researchpeer-review

37 Citations (Scopus)

Abstract

We have systematically doped pre-reacted MgB2 with C by high-energy ball milling, and obtained peak Jc (8T, 4.2K)>500Amm-2 in a form compatible with powder-in-tube wire manufacture. Effects of carbon doping by this method were qualitatively similar to single crystals and CVD (chemical-vapour-deposited) filaments, but T c, Hc2, and resistivity measurements indicate more electron scattering than in single crystals and CVD filaments of similar composition. We attribute both the high Jc(H) and the large degree of electron scattering to the high grain boundary density associated with our very fine ∼50nm grain size. At high C concentrations (C/(B+C)>0.07) J c fell sharply. We identified the cause of the Jc decline to be a sharp decline in connectivity. This work demonstrates how J c(H) of pre-reacted MgB2 can be improved by simultaneously alloying with C and refining grains through cold work and further improvement of connectivity.
Original languageEnglish
Article number011
Pages (from-to)650-657
Number of pages8
JournalSuperconductor Science and Technology
Volume20
Issue number7
DOIs
Publication statusPublished - 1 Jul 2007
Externally publishedYes

ASJC Scopus subject areas

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

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