Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Co-resonant enhancement of spin-torque critical currents in spin-valves
  with synthetic-ferrimagnet free-layer   It is experimentally shown that the critical current for onset of spin-torque
instability in current-perpendicular-to-plane spin-valves can be strongly
enhanced using "synthetic ferrimagnet" free-layers of form FM1/Ru/FM2
(FM=ferrromagnet). However, this enhancement occurs for only one polarity of
bias current. A two-macrospin model is shown to reproduce the observations. The
model suggests that this phenomenon is related to a polarity-dependent,
spin-torque induced co-resonance between the two natural dynamic modes of the
FM1/FM2 couple. The resonance condition facilitates energy transfer out of the
spin-torque destabilized mode into the other stable mode whose effective
damping is actually enhanced by spin-torques, thereby delaying the onset of
instability of this coupled system to larger critical currents.

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The categories of this paper are: hep-ex
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The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
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The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys
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The categories of this paper are: stat
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The categories of this paper are: adap-org
37
The categories of this paper are: supr-con