Resistivity scaling in granular superconductors with π junctions:: onsite dissipation dynamics

The resistivity behavior of granular superconductors containing a random distribution of pi junctions, as in high-T-c superconducting materials with d-wave symmetry, is studied numerically using Langevin dynamics with onsite dissipation of the grains. A three-dimensional XY-spin (chiral) glass is used to model the system and determine de current-voltage characteristics in the phase representation. An improved method is introduced where initial equilibrium states obtained by Monte Carlo simulations are used as initial states for the driven Langevin dynamics simulation. A superconducting (phase-coherence) transition is found at finite temperatures below which the linear resistivity vanishes and the corresponding critical exponents are determined from a dynamic scaling analysis. (C) 2004 Elsevier B.V. All rights reserved.