Dynamic magneto-optical imaging of superconducting thin films

Abstract

We present a novel method for analysis of superconducting thin films using dynamic magneto-optical imaging, revealing hallmarks of flux penetration with temporal resolution around 1 ms (in the present work) or better. This method involves investigation of transient field and dynamic current distributions, which are calculated by an inversion procedure on the Biot–Savart Law, which we show to be valid under dynamic conditions. We compare and discuss the flux front penetration speed and evolution of current distribution in high quality YBa2Cu3O thin films with that of samples deliberately damaged in such a way as to reduce critical current density without causing macroscopic damage.