Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Origin of magnetic excitation gap in double perovskite Sr$_2$FeOsO$_6$   Sr$_2$FeOsO$_6$ is an insulating double perovskite compound which undergoes
antiferromagnetic transitions at 140 K ($T_{N1}$) and 67 K ($T_{N2}$). To study
the underlying electronic and magnetic interactions giving rise to this
behavior we have performed inelastic neutron scattering (INS) and resonant
inelastic x-ray scattering (RIXS) experiments on polycrystalline samples of
Sr$_2$FeOsO$_6$. The INS data reveal that the spectrum of spin excitations
remains ungapped below T$_{N1}$, however below T$_{N2}$ a gap of 6.8 meV
develops. The RIXS data reveals splitting of the T$_{2g}$ multiplet consistent
with that seen in other 5d$^3$ osmium based double perovskites. Together these
results suggest that spin-orbit coupling is important for ground state
selection in 3d-5d$^3$ double perovskite materials.

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The categories of this paper are: q-bio
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The categories of this paper are: mtrl-th
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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: stat
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: nucl-th
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The categories of this paper are: supr-con
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The categories of this paper are: chao-dyn