Creation of a thermally assisted skyrmion lattice in Pt/Co/Ta multilayer films

Neel-type magnetic skyrmions in multilayer films have recently attracted significant attention due to their stability at room temperature and low threshold for current-driven motion, offering the potential for the construction of high-speed and high-density spintronic devices. However, to date, research studies reported in the literature have rarely examined the effect of temperature on the formation and behavior of Neel-type skyrmions. Here, we investigate the effect of the temperature on the creation of a skyrmion lattice in [Pt/Co/Ta](10) multilayer samples, using in-situ Lorentz transmission electron microscopy. By imaging the magnetization reversal process from a positive (negative) to a negative (positive) saturation, we find that the skyrmions can be created by nucleation from a ferromagnetic state and by breaking the labyrinth domains under certain external fields. More importantly, we demonstrate that the density of skyrmions in the multilayers not only depend on the external magnetic field, but also depend on the temperature and the thermal history of the materials. Published by AIP Publishing.