We report on the domain wall magnetoresistance of Co and Ni nanowires of 45
nm on diameter or less. The enhancement of the resistance due to an isolat
ed domain wall is clearly evidenced from magnetoresistance hysteresis loops
obtained under parallel and perpendicular fields. The domain walls magneto
resistance effect is by one order of magnitude smaller in Ni than in Co and
it was observed only at low temperature for Ni nanowires, The formation an
d motion of domain walls is demonstrated by MFM experiments.