Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Study of antiferromagnetic and nematic phase transitions in
  $BaFe_2(As_{1-x}P_x)_2$ by AC micro-calorimetry and SQUID magnetometry   We study the antiferromagnetic (AFM) and structural phase transitions in
single crystal $BaFe_2(As_{1-x}P_x)_2$ $(x=0, 0.3)$ at temperatures $T_N$ and
$T_S$, respectively, by high resolution ac microcalorimetry and SQUID
magnetometry. The specific heat measurements of both as grown and annealed
$BaFe_2As_2$ displays a sharp peak at the AFM/Structural transitions. A kink in
the entropy of annealed $BaFe_2As_2$ gives evidence for splitting of the two
transitions by approximately 0.5K. No additional features could be identified
in the specific heat of both $BaFe_2As_2$ and $BaFe_2(As_{0.7}P_{0.3})_2$ in
the temperature regions around $T^*$ > $T_S$ where torque measurements [S.
Kasahara et al., Nature 486, 382 (2012)] had revealed the "true" nematic phase
transition, indicating that the behavior at $T^*$ does not represent a 2nd
order phase transition, and that the phase transition of
$BaFe_2(As_{1-x}P_x)_2$ into the orthorhombic phase does occur at $T_S$.

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The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
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The categories of this paper are: comp-gas
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
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The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: ao-sci
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The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: nucl-th
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The categories of this paper are: nlin
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The categories of this paper are: q-alg