Displacement of domain walls under a nanocontact current: Mechanism for magnetoresistance asymmetric switching

We study the action of a magnetic field induced by nanocontact current puls es on the domain walls in thin magnetic films. We show that the pulses of a certain current direction shift the wall to the contact. Such an effect of attraction of the wall to the nanocontact does not depend on the initial p osition of the wall relative to the contact and results in an increase of n anocontact magnetoresistance. The opposite pulses repel this wall from the contact, i.e., the field action depends on the current direction. Our calcu lations explain experimental data relating to magnetoresistance devices. (C ) 2001 American Institute of Physics.