Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dynamic exchange coupling in magnetic bilayers   A long-ranged dynamic interaction between ferromagnetic films separated by
normal-metal spacers is reported, which is communicated by nonequilibrium spin
currents. It is measured by ferromagnetic resonance (FMR) and explained by an
adiabatic spin-pump theory. In FMR the spin-pump mechanism of spatially
separated magnetic moments leads to an appreciable increase in the FMR line
width when the resonance fields are well apart, and results in a dramatic
line-width narrowing when the FMR fields approach each other.

27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat