Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin Order due to Orbital Fluctuations: Cubic Vanadates   We investigate the highly frustrated spin and orbital superexchange
interactions in cubic vanadates. The fluctuations of $t_{2g}$ orbitals trigger
a {\it novel mechanism of ferromagnetic interactions} between spins S=1 of
V$^{3+}$ ions along one of the cubic directions which operates already in the
absence of Hund's rule exchange $J_H$, and leads to the C-type
antiferromagnetic phase in LaVO$_3$. The Jahn-Teller effect can stabilize the
orbital ordering and the G-type antiferromagnetic phase at low temperatures,
but large entropy due to orbital fluctuations favors again the C-phase at
higher temperatures, as observed in YVO$_3$.

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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-ex
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The categories of this paper are: astro-ph
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The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an