Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetoresistance and Hall Effect in the Ferromagnetic Semiconductor
  GaMnAs   The resistivity, temperature, and magnetic field dependence of the anomalous
Hall effect in a series of metallic Ga1-xMnxAs thin films with 0.015=<x=<0.08
is presented. A quadratic dependence of the anomalous Hall resistance on the
resistivity is observed, with a magnitude which is in agreement with Berry
phase theories of the anomalous Hall effect in dilute magnetic semiconductors.

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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: stat
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: nlin
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The categories of this paper are: nucl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: quant-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-alg
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The categories of this paper are: cmp-lg