Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Role of charge carriers for ferromagnetism in cobalt-doped rutile TiO2   Electric and magnetic properties of a high temperature ferromagnetic oxide
semiconductor, cobalt-doped rutile TiO2, are summarized. The cobalt-doped
rutile TiO2 epitaxial thin films with different electron densities and cobalt
contents were grown on r-sapphire substrates with laser molecular beam epitaxy.
Results of magnetization, magnetic circular dichroism, and anomalous Hall
effect measurements were examined for samples with systematically varied
electron densities and cobalt contents. The samples with high electron
densities and cobalt contents show the high temperature ferromagnetism,
suggesting that charge carriers induce the ferromagnetism.

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The categories of this paper are: hep-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
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The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
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The categories of this paper are: q-fin
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The categories of this paper are: dg-ga
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The categories of this paper are: chem-ph
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The categories of this paper are: eess
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The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
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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: patt-sol
3
The categories of this paper are: physics