Magnetic Skyrmions in Synthetic Ferri- and Antiferromagnets

Magnetic skyrmions have generated a lot of interest due to their distinct physical properties derived from their unique topology, which can be characterized by their winding number or topological charge. At the same time synthetic ferri- and antiferromagnets provide an opportunity for coupling two magnetic skyrmions with opposite topological charges resulting in novel behaviors. This presentation will discuss two possible physical representations of these systems. One is given by multilayers where the antiferromagnetic coupling comes from interlayer exchange coupling through a non-magnetic layer. Micromagnetic simulations showed how the dynamics of these systems depends sensitively on the interplay between exchange and dipolar coupling. Another system are inversion-broken multilayers of rare earth and transition metal systems. Here temperature allows to control the magnetization of the individual skyrmions, and in fact temperature can result also in a change from out-of-plane to in-plane anisotropy and a concomitant spin-reorientation transition. Repeated cycling through this transition shows that the topology of the spin textures is preserved during this continuous deformation.