Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Study of negative thermal expansion in the frustrated spinel ZnCr2Se4   The origin of negative thermal expansion (NTE) in the bond frustrated
ZnCr2Se4 has been explored. ESR and FTIR document an ideal paramagnetic state
above 100 K, below which ferromagnetic clusters coexist with the paramagnetic
state down to TN. By fitting the inverse susceptibility above 100 K using a
modified paramagnetic Curie-Weiss law, an exponentially changeable exchange
integral J is deduced. In the case of the variable J, magnetic exchange and
lattice elastic energy couple with each other effectively via magnetoelastic
interaction in the ferromagnetic clusters, where NTE occurs at a loss of
exchange energy while a gain of lattice elastic one.

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The categories of this paper are: cs
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc