Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin-density-wave transition of (TMTSF)$_2$PF$_6$ at high magnetic
  fields   The transverse magnetoresistance of the Bechgaard salt (TMTSF)$_2$PF$_6$ has
been measured for various pressures, with the field up to 24 T parallel to the
lowest conductivity direction c$^{\ast}$. A quadratic behavior is observed in
the magnetic field dependence of the spin-density-wave (SDW) transition
temperature $T_{\rm {SDW}}$. With increasing pressure, $T_{\rm {SDW}}$
decreases and the coefficient of the quadratic term increases. These results
are consistent with the prediction of the mean-field theory based on the
nesting of the quasi one-dimensional Fermi surface. Using a mean field theory,
$T_{\rm {SDW}}$ for the perfect nesting case is estimated as about 16 K. This
means that even at ambient pressure where $T_{\rm {SDW}}$ is 12 K, the SDW
phase of (TMTSF)$_2$PF$_6$ is substantially suppressed by the
two-dimensionality of the system.

10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an