VORTICES IN 2-DIMENSIONAL SUPERCONDUCTING WEAKLY COUPLED WIRE NETWORKS

We have fabricated superconducting weakly coupled wire networks made i n thin amorphous niobium-silicon films of high normal-state resistivit y and have investigated vortex dynamics in these networks. For the tem peratures of interest, the wires have a width in the order of, and a l ength much larger than the Ginzburg-Landau (GL) coherence length. We f ind that the vortex mobility in the wire networks is much lower than i n Josephson junction arrays. The ratio of the length of the single wir es to the GL coherence length determines whether a Kosterlitz-Thouless -Berezinskii transition can be observed in zero field, as well as osci llations at low temperatures in the magnetoresistance. At low temperat ures the critical current does not show oscillations in a magnetic fie ld, which might be a consequence of the existence of special vortex co nfigurations in networks with a linear current-phase relation.