Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pressure-induced Superconductivity in a Ferromagnet UGe$_2$ --
  Resistivity Measurements in Magnetic Field --   The electrical resistivity measurements in the magnetic field are carried out
on the pressure-induced superconductor UGe$_2$. The superconductivity is
observed from 1.06 to 1.44 GPa. The upper critical field of $H_{C2}$ is
anisotropic where $H_{C2}(T)$ exhibits positive curvature for $H//b$ and
$c$-axis. The characteristic enhancement of $H_{C2}$ is reconfirmed for
$H//a$-axis. In the temperature and field dependence of resistivity at $P >
P_{C}$ where the ferromagnetic ordering disappears, it is observed that the
application of the external field along the {\it a}-axis increases the
coefficient of Fermi liquid behavior $AT^{2}$ correspondingly to the
metamagnetic transition.

7
The categories of this paper are: hep-th
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The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th