Current-induced skyrmion motion is studied with theory and simulation of micromagnetism. Compared with those in the nanostripe, the maximum driving current density (J_max) and the maximum skyrmion speed (V_max) increase significantly in a fluted nanostripe structure which provides greater skyrmion-edge repulsion force to suppress transverse displacement of the skyrmion. As the driving current density increases, the skyrmion speed increases to V_max, and then decreases or remains unchanged. As increasing the edge width or thickness, J_max and V_max increase linearly. We show dependence of the skyrmion speed on edge thickness and width in the fluted nanostripe and explain theoretically with micromagnetics. It provides guidance for the design and development of spintronic devices based on nanostripes.

Magnetization reversal dynamics of NiFe nanofilm elements were studied with micromagnetic simulation. Magnetization reversal and spin-wave dynamic properties are effectively tuned by tailoring end shape of NiFe nanofilm elements. As magnetization reversal occurs,it is accompanied by a soft magnetic mode whose spacial symmetry determines initial steps(onset) of microscopic magnetization phase transitions path. There exists a critical tapered parameter h₀. For elements with tapering parameter h<h₀, reversal is achieved by nucleation of reversed domain at element ends and its irreversible expansion through domain wall movement toward central area of element. It is softening of edge mode that triggers magnetization reversal. For elements with h ≥ h₀, reversal is realized by quasi-uniform rotation of magnetization, which is induced by softening of fundamental mode.>