Vortex-antivortex dynamics in superconductor-antiparallel magnetic dipoles bilayers

Artificial superconductor (S)/ferromagnet (F) hybrid structures composed by a S film and textured F layer have attracted great interest in the last fifteen years. In the limit of high values of magnetic moments, the ferromagnetic layer filled with magnetic particles (dipoles, nanodiscs, microrings, bars, etc.) can induce spontaneous creation and stabilization of vortex-antivortex (v-av) pairs in the S layer. These v-av molecules interact strongly with external applied currents inducing their annihilation or movement. Despite numerous studies about this subject, only a few of them emphasize the microscopic nature of this phenomena. In this work, the intricate dynamics of v-av molecules birth-death events and how this process influences macroscopic quantities are investigated.