Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic properties and thermal expansion of YbGa$_x$Ge$_{2-x}$ (0.9 <=
  x <= 1.5)   The composition dependence of the Yb valence and of the thermal expansion
have been studied in the YbGa$_x$Ge$_{2-x}$ system. X-ray diffraction reveals
that single-phased samples isostructural to YbGaGe are obtained in the range of
0.9 <= x <= 1.5. The magnetic susceptibility shows that the systems are almost
nonmagnetic below room temperature, indicating a stable Yb2+ state for the x
range 0.9 <= x <= 1.5. The lattice constants as well as the lattice volume of
these systems are found to decrease monotonically with decreasing temperature,
suggesting the absence of zero thermal-expansion previously reported for
YbGaGe.

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The categories of this paper are: astro-ph
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The categories of this paper are: comp-gas
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
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The categories of this paper are: cs
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The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
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The categories of this paper are: q-fin
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The categories of this paper are: q-alg
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ph
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
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The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con