THE GEOMETRICAL EDGE BARRIER IN TYPE-I SUPERCONDUCTORS

The magneto-optical technique was used to study the edge barrier for f lux entry in type I superconducting strips (In, ph). The width of the flux-free zones appearing at the sample edges, due to the barrier, was measured at different applied fields and temperatures. Standard I-V m easurements allowed us to study the critical current originated by the edge barrier in these pinning-free samples and its dependence on diff erent parameters like magnetic field, temperature and sample's size. O ur results confirm the geometrical origin of this edge barrier and sho w its dependence on different relevant variables.