Writing Skyrmions with a Magnetic Dipole

TL;DR

This paper demonstrates numerically that magnetic dipoles can be used to write skyrmions in thin magnetic films, exploring various scenarios and developing an analytical model to explain the processes involved.

Contribution

The study introduces new methods for writing skyrmions using magnetic dipoles, supported by numerical simulations and an analytical model, advancing potential data storage techniques.

Findings

Skyrmions can be nucleated by magnetic dipoles in different scenarios.

An analytical model agrees with numerical simulations.

Multiple techniques for skyrmion writing are proposed.

Abstract

We demonstrate numerically on large spin lattices that one can write skyrmions in a thin magnetic film with a magnetic dipole of a few tens of nanometer in size. Nucleation of non-chiral skyrmions as well as chiral skyrmions formed by the Dzyaloshinskii-Moriya interaction has been investigated. Analytical model is developed that agrees with numerical results. It is shown that skyrmions can be written though a number of scenarios that depend on the experimental technique and parameters of the system. In one scenario, that branches into subscenarios of different topology, the magnetic dipole on approaching the film creates a skyrmion-antiskyrmion pair. As the dipole moves closer to the film it induces collapse of the antiskyrmion and creation of a non-zero topological charge due to the remaining skyrmion. In a different scenario the dipole moving parallel to the film nucleates a skyrmion at the boundary and then drags it inside the film. Possible implementations of these methods for writing topologically protected information in a magnetic film are discussed.