Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Self-Consistent Local Mean-Field Theory for Phase Transitions and
  Magnetic Properties of FeRh   FeRh has a phase transition from an antiferromagnetic state (low temperature)
to a ferromagnetic state (high temperature) at 360 K. Various explanations for
this behavior have been proposed over the past 20 years. However, many of the
mechanisms are inconsistent with all the data. Early models were Ising-like,
but the large anisotropy fields necessary for this are not found in hysteresis
curves. Using a four-spin Hamiltonian, we obtain a complete theoretical
description of the field and temperature phase diagram and the magnetic
properties for FeRh. The theoretical results are in good agreement with
experiments. We use our approach to predict changes in behavior as a function
of the thickness of an FeRh film. We find the four-spin Hamiltonian is
particularly sensitive to the presence of a surface, with thinner films
remaining ferromagnetic over a larger temperature range because the four-spin
contribution to the energy (which favors the antiferromagnetic state) is
smaller.

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The categories of this paper are: eess
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: q-bio
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The categories of this paper are: nlin
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The categories of this paper are: stat
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The categories of this paper are: acc-phys
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The categories of this paper are: econ
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The categories of this paper are: astro-ph
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The categories of this paper are: mtrl-th
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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: physics
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The categories of this paper are: adap-org
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The categories of this paper are: cmp-lg