Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electrical transport in the ferromagnetic state of manganites:
  Small-polaron metallic conduction at low temperatures   We report measurements of the resistivity in the ferromagnetic state of
epitaxial thin films of La_{1-x}Ca_{x}MnO_{3} and the low temperature specific
heat of a polycrystalline La_{0.8}Ca_{0.2}MnO_{3}. The resistivity below 100 K
can be well fitted by \rho - \rho_{o} = E \omega_{s}/sinh^{2}(\hbar
\omega_{s}/2k_{B}T) with \hbar \omega_{s}/k_{B} \simeq 100 K and E being a
constant. Such behavior is consistent with small-polaron coherent motion which
involves a relaxation due to a soft optical phonon mode. The specific heat data
also suggest the existence of such a phonon mode. The present results thus
provide evidence for small-polaron metallic conduction in the ferromagnetic
state of manganites.

11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
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The categories of this paper are: nlin
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: quant-ph
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The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph