  In this work we study the oscillations of the skyrmion cores in a multilayer
nanodot as a function of the number of skyrmions hosted in the system. When all
the skyrmions in the nanodot have the same core radius, and after applying a
perpendicular spin-polarized current, a relaxation process takes place towards
an equilibrium configuration that is accompanied by coherent damped
oscillations of the skyrmion cores, whose frequency depends on the number of
skyrmions present in the nanodot. Additionally, we found that the oscillation
frequency is directly related to the total energy of the system.
