Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Neutron Scattering Study of Spin Density Wave Order in the
  Superconducting State of Excess-Oxygen-Doped La2CuO4+y   We report neutron scattering measurements of spin density wave order within
the superconducting state of a single crystal of predominately stage-4
La2CuO4+y with a Tc(onset) of 42 K. The low temperature elastic magnetic
scattering is incommensurate with the lattice and is characterized by
long-range order in the copper-oxide plane with the spin direction identical to
that in the insulator. Between neighboring planes, the spins exhibit
short-range correlations with a stacking arrangement reminiscent of that in the
undoped antiferromagnetic insulator. The elastic magnetic peak intensity
appears at the same temperature within the errors as the superconductivity,
suggesting that the two phenomena are strongly correlated. These observations
directly reveal the persistent influence of the antiferromagnetic order as the
doping level increases from the insulator to the superconductor. In addition,
our results confirm that spin density wave order for incommensurabilities near
1/8 is a robust feature of the La2CuO4-based superconductors.

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The categories of this paper are: hep-ex
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The categories of this paper are: physics
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The categories of this paper are: dg-ga
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The categories of this paper are: nlin
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The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
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The categories of this paper are: stat
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-alg
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The categories of this paper are: funct-an
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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
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The categories of this paper are: quant-ph
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The categories of this paper are: chao-dyn