Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin waves in thin films and magnonic crystals with
  Dzyaloshinskii-Moriya interactions   The influence of the Dzyaloshinskii-Moriya interaction in ultra-thin
ferromagnetic films and chiral magnonic crystals on the behavior of spin waves
is reviewed. During the last decade, it has been shown, both theoretically and
experimentally, that this anisotropic exchange interaction produces
non-reciprocal features on the spin-wave spectrum of a magnetic system, a
phenomenon that occurs both for bulk and interfacial Dzyaloshinskii-Moriya
coupling. More recently, the concept of a chiral magnonic crystal has been
introduced, where the interfacial Dzyaloshinskii-Moriya interaction is
periodic. The effect of this periodicity include additional features such as
flat bands, indirect gaps, and an unusual spin-wave evolution.

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The categories of this paper are: math
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
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The categories of this paper are: nlin
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an