Domain wall ratchet effect in a magnetic wire with asymmetric notches

Current-driven domain wall (DW) motion in a magnetic wire with asymmetric notches under an external magnetic field was investigated by means of magnetic force microscopy. It was found that the reduction rate in the critical current density by the application of a magnetic field depended on the direction of the DW propagation. This suggests the existence of the asymmetric pinning potential in the notch, resulting in the DW ratchet effect. (C) 2008 American Institute of Physics.