Micromagnetic study of the frequency response of skyrmions in magnetic multilayers

Magnetic skyrmions are localized magnetization entities with a particle-like feature due to the topological stability. Often considered as promising information carriers, they can exhibit a variety of dynamics beyond the rigid translational motion, such as breathing mode and gyration. These modes are at the key ingredient for skyrmion-based oscillators and detectors. These modes become even more interesting when considering skyrmions in magnetic multilayers. Here, we analyze, within a micromagnetic framework, the frequency response of skyrmions in different magnetic multilayers, as a function of the number of ferromagnetic repetitions and/or number of skyrmions. We observe the presence of a main frequency peak related to the breathing mode, as well as the emergence of additional peaks linked to the number of repetitions and skyrmions. Our achievement can be useful for the design of the next generation of microwave devices based on skyrmions. 1