  Magnetic skyrmions are topological solitons that exhibit an increased
stability against annihilation, and can be displaced with low current
densities, making them a promising candidate as an information carrier. In
order to demonstrate a viable skyrmion-based memory device, it is necessary to
reliably and reproducibly nucleate, displace, detect, and delete the magnetic
skyrmions. While the skyrmion displacement and detection have both been
investigated in detail, much less attention has been dedicated to the study of
the sub-ns dynamics of the skyrmion nucleation process. Only limited studies on
the statics and above-ns dynamics have been performed, leaving still many open
questions on the dynamics of the nucleation process. Furthermore, the vast
majority of the presently existing studies focus on the nucleation from random
natural pinning sites, or from patterned constrictions in the magnetic material
itself, which limit the functionality of the skyrmion-based device. Those
limitations can be overcome by the fabrication of a dedicated injector device
on top of the magnetic material. In this study, we investigate the nucleation
of magnetic skyrmions from a dedicated nano-engineered injector, demonstrating
the reliable magnetic skyrmion nucleation at the remnant state. The sub-ns
dynamics of the skyrmion nucleation process were also investigated, allowing us
to shine light on the physical processes driving the nucleation.
