Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of Kosterlitz-Thouless spin correlations in the colossally
  magnetoresistive layered manganite $La_{1.2}Sr_{1.8}Mn_{2}O_{7}$   The spin correlations of the bilayer manganite $La_{1.2}Sr_{1.8}Mn_{2}O_{7}$
have been studied using neutron scattering. On cooling within the paramagnetic
state, we observe purely two-dimensional behavior with a crossover to
three-dimensional scaling close to the ferromagnetic transition. Below $T_C$,
an effective finite size behavior is observed. The quantitative agreement of
these observations with the conventional quasi two-dimensional
Kosterlitz-Thouless model indicates that the phase transition is driven by the
growth of magnetic correlations, which are only weakly coupled to polarons
above $T_C$.

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The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
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The categories of this paper are: cs
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The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio