Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic and Transport Properties in $CoSr_2Y_{1-x}Ca_xCu_2O_7$
  ($x$=0$\sim$0.4)   Magnetic and transport properties of $Co Sr_2 Y_{1-x} Ca_x Cu_2 O_7$ ($x=0
\sim 0.4$) system have been investigated. A broad maximum in M(T) curve,
indicative of low-dimensional antiferromagnetic ordering originated from
$CoO_{1+\delta}$ layers, is observed in Ca-free sample. With increasing Ca
doping level up to 0.2, the M(T) curve remains almost unchanged, while
resistivity is reduced by three orders. Higher Ca doping level leads to a
drastic change of magnetic properties. In comparison with the samples with
$x=0.0 \sim 0.2$, the temperature corresponding to the maximum of M(T) is much
lowered for the sample $x$=0.3. The sample $x$=0.4 shows a small kink instead
of a broad maximum and a weak ferromagnetic feature. The electrical transport
behavior is found to be closely related to magnetic properties for the sample
$x$=0.2, 0.25, 0.3, 0.4. It suggests that $CoO_{1+\delta}$ layers are involved
in charge transport in addition to conducting $CuO_2$ planes to interpret the
correlation between magnetism and charge transport. X-ray photoelectron
spectroscopy studies give an additional evidence of the the transfer of the
holes into the $CoO_{1+\delta}$ charge reservoir.

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The categories of this paper are: econ
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: q-bio
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The categories of this paper are: hep-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: quant-ph
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The categories of this paper are: physics
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The categories of this paper are: supr-con
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The categories of this paper are: math
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The categories of this paper are: funct-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin