Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: New heat treatment to prepare high quality polycrystalline and single
  crystal MgB2 in single process   We report here on a new heat treatment to prepare both dense polycrystalline
and single crystal MgB2 high quality samples in one single process. Resistivity
measurements for polycrystalline part of the sample gives a residual
resistivity ratio RRR=16.6 and a very low normal state resistivity rho(40K)=
0.28 microOhmcm. Both SEM and SQUID study on polycrystals reveal the high
quality, dense character and well coupling of grain boundaries. On the other
hand, the high quality single crystals have a unique shape that resembles the
hexagonal crystal structure. SQUID measurements reveals very weak flux pinning
character implying our single crystals to be very clean. In this study, we
conclude that heat treatment is playing a major rule on the characteristics of
both polycrystalline and single crystal MgB2. Samples are thoroughly
characterized by x-ray, resistivity, dc SQUID and SEM.

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The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
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The categories of this paper are: eess
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
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The categories of this paper are: nucl-th
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The categories of this paper are: math