Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Enhancement of the critical current density and flux pinning of MgB2
  superconductor by nanoparticle SiC doping   Doping of MgB2 by nano-SiC and its potential for improvement of flux pinning
was studied for MgB2-x(SiC)x/2 with x = 0, 0.2 and 0.3 and a 10wt% nano-SiC
doped MgB2 samples. Co-substitution of B by Si and C counterbalanced the
effects of single-element doping, decreasing Tc by only 1.5K, introducing
pinning centres effective at high fields and temperatures and enhancing Jc and
Hirr significantly. Compared to the non-doped sample, Jc for the 10wt% doped
sample increased by a factor of 32 at 5K and 8T, 42 at 20K and 5T, and 14 at
30K and 2T. At 20K, which is considered to be a benchmark operating temperature
for MgB2, the best Jc for the doped sample was 2.4x10^5A/cm2 at 2T, which is
comparable to Jc of the best Ag/Bi-2223 tapes. At 20K and 4T, Jc was
36,000A/cm2, which was twice as high as for the best MgB2 thin films and an
order of magnitude higher than for the best Fe/MgB2 tapes. Because of such high
performance, it is anticipated that the future MgB2 conductors will be made
using the formula of MgBxSiyCz instead of the pure MgB2.

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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: stat
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The categories of this paper are: nlin
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The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-bio
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: cs