Manipulating 1-dimensional skyrmion motion by the external magnetic field gradient

We have investigated an approximated analytic form of the one-dimensional motion of skyrmions accelerated by a gradient of the external magnetic field. We find excellent agreement between the analytical calculations and micromagnetic simulations when the skyrmion size is large. The skyrmion motion is related to not only the skyrmion size but also the skyrmion wall width. We also have performed the numerical calculation without approximation in comparison. The numerical calculation results are entirely in agreement with those of micromagnetic simulation for all the skyrmion size. These results introduce an efficient control of skyrmions to next-generation spintronic devices.