Abstract
A system of two coplanar superconducting films seamlessly connected by a bridge is studied. We observe two distinct resistive transitions as the temperature is reduced. The first one, occurring in the films, shows some properties of the Berezinskii-Kosterlitz-Thouless (BKT) transition. The second apparent transition (which is in fact a crossover) is related to freezing out of thermally activated phase slips (TAPS) localized on the bridge. We also propose a powerful indirect experimental method allowing an extraction of the sample’s zero-bias resistance from high-current-bias measurements. Using direct and indirect measurements, we have determined the resistance of the bridges within a range of eleven orders of magnitude. Over such broad range the resistance follows a simple relation , where is the normalized free energy of a phase slip at zero temperature, is normalized temperature, and is the normal resistance of the bridge.
- Received 11 December 2003
DOI:https://doi.org/10.1103/PhysRevB.70.214506
©2004 American Physical Society