Fluxons in stacked Josephson junctions at low magnetic fields

The shape of Josephson vortex (fluxon) and fluxon distribution in stacked J osephson junctions (SJJs) at low parallel magnetic fields were studied. Flu xon solution for arbitrary number of SJJs is derived. For comparison with H TSC, large scale numerical simulations with N = 600 long SJJs are presented . Due to electromagnetic coupling of SJJs, multiple quasi-equilibrium fluxo n configurations (modes) exist in SJJs for given external conditions. In pa rticular, a single row mode was demonstrated to be more favorable than a re gular fluxon lattice at low fields. The existence of such modes results in strong fluctuations of perpendicular transport properties of SJJs. Analytic results are compared with numerical simulations and experimental data for low-T-c and high-T-c SJJs. (C) 2000 Elsevier Science B.V. All rights reserv ed.