Dynamic regimes in films with a periodic array of antidots
Nanoscale Superconductivity and Magnetism Group, Laboratory for Solid State Physics and Magnetism K.U. Leuven, Celestijnenlaan 200 D, 3001 Leuven, Belgium
Corresponding author: a email@example.com
Published online: 19 February 2004
We have studied the dynamic response of Pb thin films with a square array of antidots by means of ac susceptibility measurements. At low enough ac drive amplitudes h, vortices moving inside the pinning potential give rise to a frequency- and h-independent response together with a scarce dissipation. For higher amplitudes, the average distance travelled by vortices surpasses the pinning range and a critical state develops. We found that the boundary between these regimes smoothly decreases as T increases whereas a step-like behavior is observed as a function of field. We demonstrate that these steps in arise from sharp changes in the pinning strength corresponding to different vortex configurations. For a wide set of data at several fields and temperatures in the critical state regime, we show that the scaling laws based on the simple Bean model are satisfied.
PACS: 74.78.Na – Mesoscopic and nanoscale systems / 74.25.Sv – Critical currents / 74.78.Db – Low-Tc films
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004