Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unconventional Ferroelectric Switching via Local Domain Wall Motion in
  Multiferroic $\epsilon$-Fe2O3 Films   Deterministic polarization reversal in ferroelectric and multiferroic films
is critical for their exploitation in nanoelectronic devices. While
ferroelectricity has been studied for nearly a century, major discrepancies in
the reported values of coercive fields and saturation polarization persist in
literature for many materials. This raises questions about the atomic-scale
mechanisms behind polarization reversal. Unconventional ferroelectric switching
in $\epsilon$-Fe2O3 films, a material that combines ferrimagnetism and
ferroelectricity at room temperature, is reported here. High-resolution in-situ
scanning transmission electron microscopy (STEM) experiments and
first-principles calculations demonstrate that polarization reversal in
$\epsilon$-Fe2O3 occurs around pre-existing domain walls only, triggering local
domain wall motion in moderate electric fields of 250 - 500 kV/cm. Calculations
indicate that the activation barrier for switching at domain walls is nearly a
quarter of that corresponding to the most likely transition paths inside
$\epsilon$-Fe2O3 domains. Moreover, domain walls provide symmetry lowering,
which is shown to be necessary for ferroelectric switching. Local polarization
reversal in $\epsilon$-Fe2O3 limits the macroscopic ferroelectric response and
offers important hints on how to tailor ferroelectric properties by domain
structure design in other relevant ferroelectric materials.

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The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: quant-ph
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: cmp-lg
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The categories of this paper are: nucl-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: math
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The categories of this paper are: cs
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The categories of this paper are: mtrl-th
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The categories of this paper are: physics
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The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: stat
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The categories of this paper are: chao-dyn