Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theory of the ac spin-valve effect   The spin-valve complex magnetoimpedance of symmetric ferromagnet/normal
metal/ferromagnet junctions is investigated within the drift-diffusion
(standard) model of spin injection. The ac magnetoresistance---the real part
difference of the impedances of the parallel and antiparallel magnetization
configurations---exhibits an overall damped oscillatory behavior, as an
interplay of the diffusion and spin relaxation times. In wide junctions the ac
magnetoresistance oscillates between positive and negative values, reflecting
resonant amplification and depletion of the spin accumulation, while the line
shape for thin tunnel junctions is predicted to be purely Lorentzian. The ac
spin-valve effect could be a technique to extract spin transport and spin
relaxation parameters in the absence of a magnetic field and for a fixed sample
size.

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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg
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The categories of this paper are: gr-qc
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: stat
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The categories of this paper are: astro-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-th
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The categories of this paper are: q-fin
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The categories of this paper are: comp-gas
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The categories of this paper are: nlin
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The categories of this paper are: chem-ph