Spin accumulation and resistance due to a domain wall

Starting from the kinetic equation for the Wigner function, we study the spin-accumulation mechanism of excess resistance in a domain wall. The magnetization induced around the wall is calculated in local (rotated) coordinates. Compared to the spin-diffusion length of the longitudinal magnetization, that of the transverse one is greatly reduced due to the fast precession of the magnetization vector in the local exchange field. Consequently, a considerable quenching of the spin-accumulation mechanism is predicted. For a Bloch wall in cobalt, the excess resistance due to this mechanism is 10^-3--10^-4 of the value expected for the interface with an abrupt rotation of the magnetization vector. Thus, contrary to the suggestion of Ebels et al. [Phys. Rev. Lett. 84, 983 (2000)], the spin accumulation mechanism cannot explain the large excess resistance observed on thin cobalt wires.