Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Switching of perpendicular magnetization by spin-orbit torques in the
  absence of external magnetic fields
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th