Dissipation in ultra-thin current-carrying superconducting bridges; evidence for quantum tunneling of Pearl vorticesF. Tafuri1, J. R. Kirtley2, D. Born3, D. Stornaiuolo3, P. G. Medaglia4, P. Orgiani4, G. Balestrino4 and V. G. Kogan5
1 Dipartimento di Ingegneria dell'Informazione Seconda Università di Napoli Aversa (CE), Italy
2 IBM Watson research center - Route 134 Yorktown Heights, NY 10598, USA
3 CNR-INFM Coherentia, Dipartimento di Scienze Fisiche Università di Napoli "Federico II" - Napoli, Italy
4 CNR-INFM Coherentia, Dipartimento di Ingegneria Meccanica Università di Roma Tor Vergata - Roma, Italy
5 Ames Laboratory-DOE and Department of Physics and Astronomy Iowa State University - Ames, IA 50011-3160, USA
received 8 November 2005; accepted in final form 26 January 2006
published online 15 February 2006
We have made zero-field current-voltage (IV) measurements of artificially layered high-Tc thin-film bridges. SQUID microscopy of these films provides Pearl lengths longer than the bridge widths, and shows current distributions that are uniform across the bridges. At high temperatures and high currents the voltages follow the power law , with , in good agreement with the predictions for thermally activated vortex motion. At low temperatures, the IV's are better fit by linear in I-2, as expected if the low-temperature dissipation is dominated by quantum tunneling of individual Pearl vortices.
74.25.Qt - Vortex lattices, flux pinning, flux creep.
74.78.Bz - High-Tc films.
74.78.Fk - Multilayers, superlattices, heterostructures.
© EDP Sciences 2006