Current-driven domain wall motion in thin ferromagnetic wires

The coupling between a current and a Bloch wall is examined in the half-metal limit of the double exchange model. The conduction electrons transfer angular momentum to the Bloch wall with 100% efficiency in the absence of pinning. The wall is displaced without distortion with velocity proportional to the current. In the presence of a pinning potential either the angular momentum is destroyed by the perpendicular component of the anisotropy field or is converted to coherent magnons. A moving wall has its velocity reduced by pinning. The expression for the velocity agrees surprisingly well with experiment.