Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermodynamics of layered Heisenberg magnets with arbitrary spin   We present a spin-rotation-invariant Green-function theory of long- and
short-range order in the ferro- and antiferromagnetic Heisenberg model with
arbitrary spin quantum number S on a stacked square lattice. The thermodynamic
quantities (Curie temperature T_C, N\'eel temperature T_N, specific heat C_V,
intralayer and interlayer correlation lengths) are calculated, where the
effects of the interlayer coupling and the S dependence are explored. In
addition, exact diagonalizations on finite two-dimensional (2D) lattices with
S>=1 are performed, and a very good agreement between the results of both
approaches is found. For the quasi-2D and isotropic 3D magnets, our theory
agrees well with available quantum Monte Carlo and high-temperature
series-expansion data. Comparing the quasi-2D S=1/2 magnets, we obtain the
inequalities T_N>T_C and, for small enough interlayer couplings, T_N<T_C. The
results for C_V and the intralayer correlation length are compared to
experiments on the quasi-2D antiferromagnets Zn_2VO(PO_4)_2 with S=1/2 and
La_2NiO_4 with S=1, respectively.

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The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
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The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
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The categories of this paper are: atom-ph
1
The categories of this paper are: cs
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The categories of this paper are: gr-qc
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph