Stabilization of Skyrmions in a Nanodisk Without an External Magnetic Field

We study, in the absence of a magnetic field, the stability of skyrmions in a disk-shaped ferromagnetic multilayer in the presence of locally pinned spins at the edge. This particular boundary condition suppresses the formation of helical states yet enhances the stabilization of states with rotational symmetry, such as N\'eel skyrmions. Numerical simulation shows that the size of the disk is a viable parameter to control the creation and annihilation of skyrmionic states. We also find that the demagnetization field renormalizes the Dzyaloshinskii-Moriya interaction. This study opens an alternative avenue to the generation, stabilization, and control of magnetic skyrmions in field-free heterostructures.