Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin transport in multilayer systems with fully epitaxial NiO thin films   We report on the generation and transport of thermal spin currents in fully
epitaxial {\gamma}-Fe$_2$O$_3$/NiO(001)/Pt and Fe$_3$O$_4$/NiO(001)/Pt
trilayers. A thermal gradient, perpendicular to the plane of the sample,
generates a magnonic spin current in the ferrimagnetic maghemite
({\gamma}-Fe$_2$O$_3$) and magnetite (Fe$_3$O$_4$) thin films by means of the
spin Seebeck effect. The spin current propagates across the epitaxial,
antiferromagnetic insulating NiO layer, before being detected in the Pt layer
by the inverse spin Hall effect. The transport of the spin signal is studied as
a function of the NiO thickness, temperature and ferrimagnetic material where
the spin current is generated. In epitaxial NiO grown on maghemite, the spin
Seebeck signal decays exponentially as a function of the NiO thickness, with a
spin-diffusion length for thermally-generated magnons of {\lambda}$_{MSDL}$ =
$1.6 \pm 0.2$ nm, largely independent on temperature. We see no enhancement of
the spin current signal as previously reported for certain temperatures and
thicknesses of the NiO. In epitaxial NiO grown on magnetite, the
temperature-averaged spin diffusion length is {\lambda}$_{MSDL}$ = $3.8 \pm
0.3$ nm, and we observe an enhancement of the spin signal when the NiO
thickness is 0.8 nm, demonstrating that the growth conditions dramatically
affect the spin transport properties of the NiO even for full epitaxial growth.
In contrast to theoretical predictions for coherent spin transport, we do not
see vastly different spin diffusion lengths between epitaxial and
polycrystalline NiO layers.

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The categories of this paper are: hep-ex
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The categories of this paper are: astro-ph
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The categories of this paper are: q-bio
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: chem-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
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The categories of this paper are: atom-ph
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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: adap-org
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The categories of this paper are: math