Role of magnetic anisotropy constant orders and thermal noise on skyrmion formation in the Co\(/\)Pt square nanostructure

Abstract

Skyrmions, which are topologically stable magnetic structures, have manifested promising features to be used as an information carrier in new-age, non-volatile data storage devices. In this article, Co\(/\)Pt square nanostructure with Co-free layer thickness in the range of 1–5 nm and first- and second-order anisotropy constants are taken to study the controlled formation of skyrmions. The magnetisation dynamics controlled by the current-induced spin transfer torque help to nucleate skyrmions by transforming the perpendicularly magnetised ground state. This process leads to a stable state of the isolated skyrmions via a complex transformation of the Neel wall following its image inversion. Skyrmion numbers vary with increasing thickness as the current density gradually increases. The impact of higher-order anisotropy constants (up to the second order) on the relaxed state of a system, compared to the first-order anisotropy alone, has been examined. Additionally, the effect of temperature on the formation of skyrmions has been analysed for all thicknesses.