Quasistatic field responses of fluxoids in an Y1Ba2Cu3O7-δ film

The quasistatic magnetic field responses (typically 0.8 Hz) of fluxoids in a c-axis oriented Y1Ba2Cu3O7-δ (Y123) film have been studied using a computerized mechanical pendulum at 77 K. The resonance frequence of the pendulum is significantly shifted to higher values due to the interaction between the Y123 film and a magnet mounted on the pendulum. The contribution of the magnet-superconductor interaction to the shift of the squared resonance frequency shows, in a certain range, a logarithmic dependence on the driving force (proportional to the amplitude). The present results are consistent with the previous studies on the bulk Y123 materials for different configuration