Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Coexistence of Superconductivity and Antiferromagnetism Probed by
  Simultaneous NMR and Electrical Transport in (TMTSF)2PF6   We report simultaneous NMR and electrical transport experiments in the
pressure range near the boundary of the antiferromagnetic spin density wave
(SDW) insulator and the metal-lic/superconducting (SC) phase in (TMTSF)2PF6.
Measurements indicate a tricritical point separat-ing a line of second order
SDW/metal transitions from a line of first order SDW/metal(SC) transi-tions
with coexistence of macroscopic regions of SDW and metal(SC) order, with little
mutual in-teraction but strong hysteretic effects. NMR results quantify the
fraction of each phase.

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The categories of this paper are: physics
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
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The categories of this paper are: stat
8
The categories of this paper are: hep-ex
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The categories of this paper are: econ
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
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The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci