Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Very large magnetoresistance in lateral ferromagnetic (Ga,Mn)As wires
  with nanoconstrictions   We have fabricated (Ga,Mn)As nanostructures in which domain walls can be
pinned by sub-10 nm constrictions. Controlled by shape anisotropy, we can
switch the regions on either side of the constriction to either parallel or
antiparallel magnetization. All samples exhibit a positive magnetoresistance,
consistent with domain-wall trapping. For metallic samples we find a
magnetoresistance up to 8%, which can be understood from spin accumulation. In
samples where, due to depletion at the constriction, a tunnel barrier is
formed, we observe a magnetoresistance of up to 2000 %.

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The categories of this paper are: mtrl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: cs
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The categories of this paper are: atom-ph
2
The categories of this paper are: math
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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
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The categories of this paper are: alg-geom
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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: q-fin
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The categories of this paper are: nlin
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The categories of this paper are: math-ph