Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unidirectional terahertz light absorption in the pyroelectric
  ferrimagnet CaBaCo4O7   Spin excitations were studied by absorption spectroscopy in CaBaCo4O7 which
is a type-I multiferroic compound with the largest magnetic-order induced
ferroelectric polarization ({\Delta}P=17mC/m2) reported, so far. We observed
two optical magnon branches: a solely electric dipole allowed one and a mixed
magnetoelectric resonance. The entangled magnetization and polarization
dynamics of the magnetoelectric resonance gives rise to unidirectional light
absorption, i.e. that magnon mode absorbs the electromagnetic radiation for one
propagation direction but not for the opposite direction. Our systematic study
of the magnetic field and temperature dependence of magnon modes provides
information about the energies and symmetries of spin excitations, which is
required to develop a microscopic spin model of CaBaCo4O7.

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The categories of this paper are: funct-an
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The categories of this paper are: adap-org
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The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
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The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess