Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Origin and pressure dependence of ferromagnetism in A2Mn2O7 pyrochlores
  (A=Y, In, Lu, and Tl)   Non-conventional mechanisms have been recently invoked in order to explain
the ferromagnetic ground state of A2Mn2O7 pyrochlores (A=Y, In, Lu and Tl) and
the puzzling decrease of their Curie temperatures with applied pressure. Here
we show, using a perturbation expansion in the Mn-O hopping term, that both
features can be understood within the superexhange model, provided that the
intra-atomic oxygen interactions are properly taken into account. An additional
coupling between the Mn ions mediated by the In(5s)/Tl(6s) bands yields the
higher Tc's of these two compounds, this mechamism enhancing their
ferromagnetism for higher pressures.

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The categories of this paper are: alg-geom
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The categories of this paper are: q-alg
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The categories of this paper are: astro-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: funct-an
9
The categories of this paper are: nlin
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
3
The categories of this paper are: physics
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat