THE THIN-FILM DISK AND RING-SHAPED TYPE-II SUPERCONDUCTORS IN PERPENDICULAR MAGNETIC-FIELDS

Properties of small, thin-film, disk-shaped and ring-shaped supercondu ctors in the presence of perpendicular magnetic fields were considered within the framework of a model that takes into account the differenc e between magnetic induction and vortex density, vortex movement, and generation of vortices if current density exceeded its critical value. The linear complex magnetic susceptibility of a ring was calculated. It was shown that the distribution of the dissipative current differed considerably from the reactive one. The influence of the edge barrier on the form of the hysteresis loop, and current and field patterns fo r the ring in the critical state were shown.