The guidance of vortex–antivortex pairs by in-plane magnetic dipoles in a superconductingfinite-size film

Abstract

The possibility of manipulating vortex matter by using various artificial pinning arrays isof significant importance for possible applications in nano and micro fluxonicsdevices. By numerically solving the time-dependent Ginzburg–Landau equations, westudy the vortex–antivortex (v–av) dynamics in a hybrid structure consisting ofa finite-size superconductor with magnetic dipoles on top which generate v–avpairs in the presence of an external current. The v–av dynamics is analyzed fordifferent arrangements and magnetic moments of the dipoles, as a function of angleα between the direction of the magnetic dipole and that of the Lorentz force produced by theapplied current. The interplay of the attractive interaction between a v–av pairand the Lorentz force leads either to the separation of (anti)vortices and theirmotion in opposite directions or to their annihilation. We found a critical angleαc, below which vortices and antivortices are repelled, while for larger angles they annihilate.In case of a single (few) magnetic dipole(s), this magnetic dipole induced v–av guidance isinfluenced by the self-interaction of the v–av pairs with their images in a finite-size sample,while for a periodic array of dipoles the guidance is determined by the interaction of a v–avpair with other dipoles and v–av pairs created by them. This effect is tunable throughthe external current and the magnetization and size of the magnetic dipoles.