Electronic transport through domain walls in ferromagnetic nanowires:Co-existence of adiabatic and non-adiabatic spin dynamics

We study the effect of a domain wall on the electronic transport in ferromagnetic quantum wires. Due to the transverse confinement,conduction channels arise. In the presence of a domain wall, spin upand spin down electrons in these channels become coupled.For very short domain walls or at high longitudinal kinetic energy, this coupling is weak, leads to very few spin flips, and a perturbative treatment is possible. For very long domain wall structures, the spin follows adiabaticallythe local magnetization orientation, suppressing the effect of thedomain wall on the total transmission, but reversing the spin of theelectrons. In the intermediate regime, we numerically investigate the spin-dependent transport behavior for different shapes of the domain wall. We find that the knowledge of the precise shape of the domain wall is not crucial for determining the qualitative behavior.For parameters appropriate for experiments, electrons with lowlongitudinal energy are transmitted adiabatically while the electronsat high longitudinal energy are essentially unaffected by the domainwall. Taking this co-existence of different regimes into accountis important for the understanding of recent experiments