Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Approach to the metal-insulator transition in La(1-x)CaxMnO3 (0<x<.2):
  magnetic inhomogeneity and spin wave anomaly   We describe the evolution of the static and dynamic spin correlations of
La$_{1-x}$Ca$_x$MnO$_3$, for x=0.1, 0.125 and 0.2, where the system evolves
from the canted magnetic state towards the insulating ferromagnetic state,
approaching the metallic transition (x=0.22).
  In the x=0.1 sample, the observation of two spin wave branches typical of two
distinct types of magnetic coupling, and of a modulation in the elastic diffuse
scattering characteristic of ferromagnetic inhomogeneities, confirms the static
and dynamic inhomogeneous features previously observed at x$<$0.1. The
anisotropic q-dependence of the intensity of the low-energy spin wave suggests
a bidimensionnal character for the static inhomogeneities. At x=0.125, which
corresponds to the occurence of a ferromagnetic and insulating state, the two
spin wave branches reduce to a single one, but anisotropic. At this
concentration, an anomaly appears at {\bf q$_0$}=(1.25,1.25,0), that could be
related to an underlying periodicity, as arising from (1.5,1.5,0)
superstructures.
  At x=0.2, the spin-wave branch is isotropic. In addition to the anomaly
observed at q$_0$, extra magnetic excitations are observed at larger q, forming
an optical branch. The two dispersion curves suggest an anti-crossing behavior
at some {\bf q$_0$'} value, which could be explained by a folding due to an
underlying perodicity involving four cubic lattice spacings.

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The categories of this paper are: eess
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-th
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The categories of this paper are: atom-ph
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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex
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The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: nlin
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The categories of this paper are: acc-phys
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The categories of this paper are: econ
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The categories of this paper are: quant-ph
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: cmp-lg