Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Anisotropic superconducting properties of aligned MgB2 crystallites   Samples of aligned MgB2 crystallites have been prepared, allowing for the
first time the direct identification of an upper critical field anisotropy
Hc2^{ab}/Hc2^{c}= xi_{ab}/xi_{c} ~ 1.73; with xi_{o,ab} ~ 70 A, xi_{o,c} ~ 40
A, and a mass anisotropy ratio m_{ab}/m_{c} ~ 0.3. A ferromagnetic background
signal was identified, possibly related to the raw materials purity.

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The categories of this paper are: chem-ph
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The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
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The categories of this paper are: funct-an
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The categories of this paper are: ao-sci
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The categories of this paper are: math-ph
1
The categories of this paper are: cs
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The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg