Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Current Induced Excitations in Cu/Co/Cu Single Ferromagnetic Layer
  Nanopillars   Current-induced magnetic excitations in Cu/Co/Cu single layer nanopillars
(~50 nm in diameter) have been studied experimentally as a function of Co layer
thickness at low temperatures for large applied fields perpendicular to the
layers. For asymmetric junctions current induced excitations are observed at
high current densities for only one polarity of the current and are absent at
the same current densities in symmetric junctions. These observations confirm
recent predictions of spin-transfer torque induced spin wave excitations in
single layer junctions with a strong asymmetry in the spin accumulation in the
leads.

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The categories of this paper are: astro-ph
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The categories of this paper are: physics
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: econ
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The categories of this paper are: eess
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The categories of this paper are: nucl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ph
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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: plasm-ph
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The categories of this paper are: math-ph