  A rich variety of specific multidomain textures recently observed in
antiferromagnetically coupled multilayers with perpendicular anisotropy include
regular (equilibrium) multidomain states as well as different types of
topological magnetic defects. Within a phenomenological theory we have
classified and analyzed the possible magnetic defects in the antiferromagnetic
ground state and determine their structures. We have derived the optimal sizes
of the defects as functions of the antiferromagnetic exchange, the applied
magnetic field, and geometrical parameters of the multilayer. The calculated
magnetic phase diagrams show the existence regions for all types of magnetic
defects. Experimental investigations of the remanent states (observed after
different magnetic pre-history) in [Co/Pt]/Ru multilayers with wedged Co layers
reveal a corresponding succession of different magnetic defect domain types.
