Ballistic electron transport through magnetic domain walls
  Electron transport limited by the rotating exchange-potential of domain walls is calculated in the ballistic limit for the itinerant ferromagnets Fe, Co, and Ni. When realistic band structures are used, the domain wall magnetoresistance is enhanced by orders of magnitude compared to the results for previously studied two-band models. Increasing the pitch of a domain wall by confinement in a nano-structured point contact is predicted to give rise to a strongly enhanced magnetoresistance. 
Jeroen B.A.N. van Hoof, Kees M. Schep, Arne Brataas, Gerrit E.W.   Bauer, and Paul J. Kelly