Domain wall mobility engineering by a perpendicular magnetic field in microwires with a gradient of perpendicular anisotropy

Fast domain wall propagation is a typical feature of amorphous glass-coated microwires with positive magnetostriction. The high domain wall velocity can be effectively tailored either by sample postprocessing or temperature. In this work, we show that the domain wall dynamics can be engineered by a perpendicular magnetic field. We perform the domain wall mobility measurements in microwires with a varying gradient of the perpendicular magnetic anisotropy. It is shown that domain wall mobility is mainly determined by counterplay between the amplitude of perpendicular anisotropy and externally applied perpendicular field. The presence of perpendicular magnetic anisotropy is observed by Scanning electron microscopy. The relation between the maximum applied perpendicular magnetic field, and the wire dimensions are provided based on the measured data.