Direct imaging of a zero-field target skyrmion and its polarity switch in a chiral magnetic nanodisk

TL;DR

This study successfully visualized and manipulated target skyrmions in a chiral magnetic nanodisk, demonstrating their stable states and polarity switching, which are promising for future magnetic memory applications.

Contribution

First direct imaging of target skyrmions in a nanodisk and demonstration of their polarity switching using electron holography.

Findings

Target skyrmions observed in 160-nm FeGe nanodisk.

Switching between degenerate skyrmion states demonstrated.

Comparison of experimental images with numerical simulations.

Abstract

A target skyrmion is a flux-closed spin texture that has two-fold 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.