We discuss the micromagnetics of two coupled layers of ultrathin films
. The spins change from a closure domain arrangement to mostly aligned
as the interlayer spacing is decreased. There are remanent domains at
the edges which serve as nucleation centers and control the switching
behavior in a field. The domain patterns are often changed after a hy
steresis cycle, consistent with recent measurement of the giant magnet
oresistance in multilayer structures. Different vorticity of the edge
domains can lead to very different zero-field remanent domain structur
es.