Spin transport in magnetic nanowires with domain walls

Abstract

We review briefly the problem of electron transport in magnetic nanowires with thin domain walls. Transmission of electrons in such structures is associated with charge and spin currents leading to the occurrence of a spin torque that acts on the domain wall. Experimentally, the properties of such structures are manifested as a large magnetoresistance, current-induced motion of the domain wall, generation of spin currents, etc. The effect of electron interactions on the scattering from a sharp domain wall is also considered in more details. Using a renormalization group approach for the interactions, we obtain scaling equations for the scattering amplitudes. The RG equations obtained are independent of the single-particle model for the domain wall. We describe the nature of the zero temperature fixed points. For repulsive interactions, the wall reflects all incident electrons at the fixed points. However, the interactions determine whether this reflection is accompanied by spin reversal or not. In one of the fixed points the wall flips the spin of all incident electrons, generating a finite spin current without an associated charge current. It is also shown that the RG flow affects short walls more quickly than long walls, implying that correlations have a more important effect on short walls.