Abstract
Magnetic skyrmions are nanoscale, stable, particle-like, topological objects in the magnetisation texture of magnetic compounds or thin films with inversion asymmetry. They can be written, deleted and moved at high velocity by small currents. These attributes make them candidates for modern high density data storage and logic devices.Skyrmion bags or heavy skyrmions are typically composed of any number of skyrmions and can thus be of arbitrary integer topological degree. This makes possible the encoding of data within a single, stable topological object which could help overcome some of the limitations of unitary-degree skyrmions such as storage density and the idea of encoding zeroes as gaps in racetrack devices.
In this thesis the initial theory and application of skyrmion bags are examined. We investigate the discovery of these objects, by the author, and their first implementation in liquid crystals with similar governing equations to micromagnetics. A relationship to help guide the construction of these objects in magnetic multilayer experiments is derived analytically
from the Thiele, collective coordinate, description of micromagnetic texture motion. Finally we examine the dynamics of varying-degree bags under spin polarised currents and conclude with ideas for the future direction of research in this area.
| Date of Award | 2 Dec 2021 |
|---|---|
| Original language | English |
| Awarding Institution |
|
| Supervisor | Valeriy Slastikov (Supervisor) & Jonathan M Robbins (Supervisor) |