Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Post-spinel transformations and equation of state in ZnGa2O4:
  Determination at high-pressure by in situ x-ray diffraction   Room temperature angle-dispersive x-ray diffraction measurements on spinel
ZnGa2O4 up to 56 GPa show evidence of two structural phase transformations. At
31.2 GPa, ZnGa2O4 undergoes a transition from the cubic spinel structure to a
tetragonal spinel structure similar to that of ZnMn2O4. At 55 GPa, a second
transition to the orthorhombic marokite structure (CaMn2O4-type) takes place.
The equation of state of cubic spinel ZnGa2O4 is determined: V0 = 580.1(9) A3,
B0 = 233(8) GPa, B0'= 8.3(4), and B0''= -0.1145 GPa-1 (implied value); showing
that ZnGa2O4 is one of the less compressible spinels studied to date. For the
tetragonal structure an equation of state is also determined: V0 = 257.8(9) A3,
B0 = 257(11) GPa, B0'= 7.5(6), and B0''= -0.0764 GPa-1 (implied value). The
reported structural sequence coincides with that found in NiMn2O4 and MgMn2O4.

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The categories of this paper are: nlin
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The categories of this paper are: cs
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The categories of this paper are: solv-int
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The categories of this paper are: hep-th
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The categories of this paper are: comp-gas
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The categories of this paper are: gr-qc
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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: math-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: stat
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The categories of this paper are: math
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The categories of this paper are: supr-con