Vortex shaking in superconducting platelets in an inclined magnetic field

Abstract

For thin superconducting platelets or films in a dc magnetic field, the application of a weakac magnetic field in the plane of the platelet allows the vortices to drift. This vortex motiongenerates a dc voltage in the superconductor that causes the critical currents andirreversible magnetic moment to relax completely. This vortex shaking was explainedquantitatively for long strips with weak ac field applied perpendicular or parallel to thecritical screening currents that flow along the strip, and for films of rectangular shape. Inall these cases the dc magnetic field was applied perpendicular to the film. The presentwork generalizes these theories to cases when the dc field is applied at an angle withrespect to the film plane. It is found that an appropriate tilt of the dc field can stronglyincrease the anisotropy of the shaking-induced relaxation and accelerates theappearance of additional current loops, so that these effects may be observed moreeasily.