Fig. 3

Structural and electrical characteristics of the nanoconstriction. (a) SEM image of a microbridge with a nanoconstriction made by FIB. The inset shows the nanoconstriction with a width of 100 nm. The current flows perpendicular to the terraces and is indicated by the white arrow. (b) Typical IV-curve of a nanoconstriction with a width of 100 nm oriented across the terraces; the extrapolation by dashed red line shows an excess current. The inset shows a typical curve of a transition from normal to superconducting state; the transition temperature of the YBCO electrodes is indicated by the dashed black arrow.