Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superconducting transition in Pb/Co nanocomposites: effect of Co volume
  fraction and external magnetic field   Pb films embedded with homogeneously distributed cobalt (Co) nanoparticles
(mean size 4.5 nm) have been prepared. Previous transport investigations have
shown that Co particles induce spontaneous vortices below the superconducting
transition temperature (T$_{c}$) in zero external magnetic field. In this paper
we study in detail the influence of the Co volume franction and an external
magnetic field on the superconducting transition in such composites. The large
difference in T$_c$-reduction between the as-prepared and annealed samples can
be attributed to the different superconducting coherence lengths and the
resulting different diameters of the spontaneous vortices in these samples.

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The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
19
The categories of this paper are: eess
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
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The categories of this paper are: hep-th
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The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex