  Magnetic domain walls can be moved by spin-polarized currents due to
spin-transfer torques. This opens the possibility to use them in spintronic
memory devices as, e.g., in racetrack storage. Naturally, in miniaturized
devices domain walls can get very close to each other and affect each others
dynamics. In this work we consider two separated domain walls in different
layers which interact via an interlayer exchange coupling. One of these walls
is moved by a spin-polarized current. Depending on several parameters as the
current density, the interlayer coupling or the pinning potential, the combined
dynamics of the two domain walls can change very strongly allowing, e.g., for a
correlated motion of the walls. In addition, more subtle effect appear as a
suppression of the Walker breakdown accompanied by an increase of the domain
wall velocity.
