Skyrmions as quasi-particles : from dynamics to application in unconventional computing

Abstract

This dissertation explores the magnetic behavior and manipulation of skyrmions - topologically protected spin textures in metallic thin films - focusing on their dynamics, confinement, and application in low-power unconventional computation. Skyrmion flow in the creep regime was studied in straight and modulated channels, revealing boundary-dependent velocity profiles in qualitative agreement with Thiele-based simulations. Controlled He+ and Ga+ irradiation enabled tuning of magnetic properties and enabled creating artificial barrier for e.g., skyrmion compression. The experimental findings of the latter are compared and supported by adapted theoretical models and simulations. A key part is the development of a novel reservoir computing (RC) scheme based on the Brownian dynamics of confined skyrmions. Even in a simplistic confining geometry like an equilateral triangle, the system performs Boolean logic operations, even nonlinear logic at ultra-low current densities. Its scalability and potential for increased complexity make skyrmion-based RC a promising platform for energyefficient, unconventional computing.