Study of jitter in domain wall displacement detection

Domain wall displacement detection (DWDD) is the promising method for achieving a linear density as high as 0.1 μm per bit. The velocity for the wall displacement was estimated to be 28 m/s from an experiment on a DWDD disk. Simulation of the driving force both by Bloch wall energy gradient and demagnetizing field proved that magnetic parameters must be optimized to obtain sufficient wall velocity for displacement. Contrary to the ordinary structured MO disk, the jitter of DWDD disk is not determined by intersymbol interference but affected by fluctuations of the front line where the wall displacement starts. Observed jitter of 10 nm was analyzed in terms of fluctuations both readout and recording