Resistance of a domain wall in a thin ferromagnetic wire

The resistivity of a ferromagnetic wire depends on the magnetic domain configuration. We describe results for very narrow Ni wires which clearly reveal the effect of a domain wall on the resistance. Interestingly, the presence of a domain wall lowers the resistance, i.e., the resistance with a wail present is lower than that of the same wire without a wall. The magnitude of this effect is consistent with a recent theoretical prediction of Tatara and Fukuyama. Other possible explanations are also discussed.