  Spin wave dispersion and damping are investigated in the metallic SDW state
of different itinerant electron models including a small interlayer hopping.
Magnetic excitations in iron pnictides are shown to be well understood in terms
of physical mechanisms characteristic of metallic magnets, such as
carrier-induced ferromagnetic spin couplings, intra-band particle-hole
excitations, and the spin-charge coupling mechanism, which is also important in
ferromagnetic manganites.
