Stabilizing skyrmions on Pt/Co/Ta multilayers and ordered arrays of nanodomes by FORC Hall analysis

Magnetic skyrmions are non-trivial spin textures that resist external disturbances and are promising candidates for the next generation of magnetic recording devices [1,2]. However, a major challenge in the realization of devices based on skyrmions is the stabilization of ordered arrangements of these spin textures under ambient temperature and zero applied field conditions. Among the materials that have skyrmions, the multilayers of ferromagnetic materials (Co) interspersed with heavy metals (Pt and Ta), with strong spin-orbit coupling, have interesting properties, as they favor the Dzyaloshinskii-Moriya (DMI) interaction, which is an anti-symmetric exchange interaction that tilts the spins of neighboring layers and helps to stabilize skyrmions. In this work we study the formation and stabilization of magnetic skyrmions in Pt/Co/Ta films by a first order reversal curves (FORC) diagram analysis, obtained from Hall Effect measurements [3]. The FORC diagram analysis was used to determine the magnetic fields to be applied to nucleate and stabilize skyrmions on the multilayers and on the nanodomes. We also demonstrate for the first time the formation and stabilization of magnetic skyrmions on arrays of self-assembled hexagonal nanodomes [4]. Magnetic force microscopy (MFM) images of the arrays of nanodomes with 100 nm shows isolated skyrmions under an out-of-plane magnetic field of only 500 Oe and at remanence, the special topography helps to stabilize the skyrmions in the hexagonal arrangement of the nanodomes. Micromagnetic simulations were compared with experiments to determine the correlation of the domain textures with the topography of the samples and with the applied field and magnetic parameters of the multilayers.