  We show that in a magnetic nanowire with double magnetic domain walls,
quantum interference results in spin-split quasistationary states localized
mainly between the domain walls. Spin-flip-assisted transmission through the
domain structure increases strongly when these size-quantized states are tuned
on resonance with the Fermi energy, e.g. upon varying the distance between the
domain walls which results in resonance-type peaks of the wire conductance.
This novel phenomena is shown to be utilizable to manipulate the spin density
in the domain vicinity. The domain walls parameters are readily controllable
and the predicted effect is hence exploitable in spintronic devices.
