Influence of Inhomogeneous Magnetic Field on Dynamic Behavior of Vortex-Antivortex Chains in the Superconductor/Ferromagnet Bilayer Structures

Using a finite element method to numerically solve the time-dependent Ginzburg–Landau equations, we studied the influence of an inhomogeneous magnetic field on the dynamic behavior of vortex–antivortex chains in the superconductor/ferromagnet bilayer structures. Our results show that the coupling effect of superconductor/ferromagnet structures manifests as the vortex–antivortex pairs interaction. The coupling effect increases with the increasing level of inhomogeneity of the magnetic field. The periodic motion of the vortex–antivortex chains leads to the periodic oscillations of the magnetization and superconducting current in the superconductor film. The frequency of oscillations is adjusted by the inhomogeneous magnetic field and the external driving current.