  We construct a set of exact ground states with a localized ferromagnetic
domain wall and an extended spiral structure in a deformed flat-band Hubbard
model. In the case of quarter filling, we show the uniqueness of the ground
state with a fixed magnetization. We discuss more realistic situation given by
a band-bending perturbation, which can stabilize these curious structures. We
study the scattering of a conduction electron by the domain wall and the spiral
spins.
