Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetoelastic-magnetoelectric phase transitions in multiferroic BiFeO3   Our measured dielectric constant and mechanical response of multiferroic
BiFeO3 indicate four phase transitions below room temperature. Features
correlate with those reported at 50K (from a peak in the zero-field-cooled
magnetic susceptibility) and 230K (from splitting between field-cooled and
zero-field-cooled magnetic data[1], and 200K (from magnon light scattering
cross sections[2]). The primary order parameter is not the polarization in any
of the low-T transitions. Instead, the transition near 230 K shows strong
elastic coupling, while that at 50K is fundamentally magnetic, but
magnetostrictively coupled to the the lattice. The low-T phase transitions
display glassy behaviour. A further anomaly at 140K interpreted as spin
reorientation[2,3] shows only weakly in dielectric and mechanical studies,
indicating that it is predominantly magnetic with little coupling to any of the
other order parameters.

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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg
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The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
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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: astro-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: quant-ph
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The categories of this paper are: supr-con
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The categories of this paper are: bayes-an
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ph
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The categories of this paper are: patt-sol