Direct Imaging of a Zero-Field Target Skyrmion and Its Polarity Switch in a Chiral Magnetic Nanodisk

Abstract

A target Skyrmion is a flux-closed spin texture that has twofold degeneracy and is promising as a binary state in next generation universal memories. Although its formation in nanopatterned chiral magnets has been predicted, its observation has remained challenging. Here, we use off-axis electron holography to record images of target Skyrmions in a 160-nm-diameter nanodisk of the chiral magnet FeGe. We compare experimental measurements with numerical simulations, demonstrate switching between two stable degenerate target Skyrmion ground states that have opposite polarities and rotation senses, and discuss the observed switching mechanism.

Magnetic structures in the locally inverted interlayer coupling region of a bilayer magnetic system

“…Similar phenomenon in three-dimensional multilayer magnetic system was reported theoretically [28] and experimentally [29][30][31]. In the structure called threedimensional skyrmion, Bloch-like skyrmions are in the middle of the film and Néel-like skyrmions are at the top and bottom surface of the film.…”

“…In the structure called threedimensional skyrmion, Bloch-like skyrmions are in the middle of the film and Néel-like skyrmions are at the top and bottom surface of the film. This structure has been observed in Fe/Gd multiplayers [29], FeGe nanodisk [30], and bulk Cu2OSeO [31]. The composite only including top layer and bottom layer of the three-dimensional skyrmion is called Néel caps.…”

The stability of a skyrmion in a nanotube

“…FeGe is one of the most widely studied chiral magnets that host magnetic skyrmions. Nanostructures made of FeGe, such as the wedge-shaped nanostripe [44], nanodisks [45,46] and nanowires [47], have been experimentally fabricated. Here we consider using chiral magnet FeGe with mesh size of´2 nm 2 nm 2 nm .…”

Realization of ordered magnetic skyrmions in thin films at ambient conditions

“…Advances, particularly in interfacial Dzyaloshinskii-Moriya (DM) interactions, 10 have largely overcome the challenges associated with room-temperature stability. 4,11 Few approaches have been demonstrated that can stabilize skyrmions at zero applied magnetic field, but include rapid quenching, 8,12 pulsed electrical currents, 13 geometric confinement, 14,15 or pinning the skyrmions with nanostructures 16,17 . These approaches place restrictions on the skyrmion system, limiting both fundamental research and eventual device architectures.…”