Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Enhanced magnon spin transport in NiFe$_2$O$_4$ thin films on a
  lattice-matched substrate
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg