Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetostriction Reveals Orthorhombic Distortion in Tetrahedral
  Gd-compounds   We report detailed thermal expansion and magnetostriction experiments on
GdCoIn$_5$ and GdRhIn$_5$ single crystal samples that show a sudden change in
the dilation at a field B$^\ast$ for temperatures below the N\'eel transition
temperature TN. We present a first-principles model including crystal-field
effects, dipolar and exchange interactions, and the dependence of the exchange
couplings with lattice distortions in order to fully account for the
magnetostriction and magnetic susceptibility data. The mean-field solution of
the model shows that a transition between metastable states occurs at the field
B$^\ast$. It also indicates that two degenerate phases coexist in the sample at
temperatures below TN. This allows to explain the lack of observation, in high
resolution x-ray experiments, of an orthorhombic distortion at the N\'eeel
transition even though the magnetic structure breaks the tetragonal symmetry
and the magnetoelastic coupling is significant. These conclusions could be
extended to other tetragonal Gd-based compounds that present the same
phenomenology.

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The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn