Chirality Control of Magnetic Vortices in Ferromagnetic Disk–Nanowire System

Abstract

The results of experimental studies and micromagnetic modeling of magnetic states in a one-dimensional array are presented. The array has the form of a chain of ferromagnetic disks coupled with a ferromagnetic nanowire made of the same material. The disks are located on opposite sides of the nanowire, which makes it possible to obtain distributions when the chiralities of the magnetic vortex shells in neighboring disks alternate, which can find application in vortex spin nanooscillators. By applying a magnetic field of an excited objective lens in situ and using Lorentz transmission electron microscopy, it is shown that in this system the chiralities of the shells of magnetic vortices can be controlled by magnetization in the sample plane along various azimuthal directions. When magnetized along the nanowire in disks located on opposite sides of it, vortex states with opposite chiralities are realized. An antivortex is formed in the nanowire itself at the boundary with the disk, since the local direction of magnetization in the wire and in the disk are anticollinear. When magnetized perpendicular to the nanowire, states with the same chirality are realized in all disks. In this case, two perpendicular domain walls are formed between the disks in the nanowire and the vortex in the disk is shifted to one of the edges along the nanowire.