Abstract
We have developed a superconducting phase gradiometer consisting of two parallel DNA-templated nanowires connecting two thin-film leads. We have ramped the cross current flowing perpendicular to the nanowires, and observed oscillations in the lead-to-lead resistance due to cross-current-induced phase differences. By using this gradiometer we have measured the temperature- and magnetic-field dependence of the superfluid density, and observed an amplification of phase gradients caused by elastic vortex displacements. We examine our data in light of Miller-Bardeen theory of dirty superconductors and a microscale version of Campbell’s model of field penetration.
- Received 26 September 2007
DOI:https://doi.org/10.1103/PhysRevB.76.220506
©2007 American Physical Society