FLUXON DYNAMICS IN DISCRETE JOSEPHSON TRANSMISSION-LINES WITH STACKEDJUNCTIONS

The experimental and numerical study of parallel one-dimensional array s consisting of double-layer stacked small Josephson tunnel junctions is reported. In addition to several features already known for classic single-layer arrays, we find a new resonant state which corresponds t o the locking of the fluxon oscillations to a frequency of small-ampli tude oscillations of the superconducting phase in middle islands of sm all stacks. Numerical simulations of a simplified circuit agree well w ith experiments and confirm the suggested qualitative mechanism. In th ese experiments we find no indication for the so-called multiple-fluxo n propagation in double-junction arrays. (C) 1997 American Institute o f Physics.