Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic Determination of $H_{c2}$ under Accurate Alignment in
  (TMTSF)$_2$ClO$_4$   Cantilever magnetometry has been used to measure the upper critical magnetic
field $H_{c2}$ of the quasi-one dimensional molecular organic superconductor
(TMTSF)$_2$ClO$_4$. From simultaneous resistivity and torque magnetization
experiments conducted under precise field alignment, $H_{c2}$ at low
temperature is shown to reach 5T, nearly twice the Pauli paramagnetic limit
imposed on spin singlet superconductors. These results constitute the first
thermodynamic evidence for a large $H_{c2}$ in this system and provide support
for spin triplet pairing in this unconventional superconductor

7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol