COMPUTATIONAL DETERMINATION OF CRITICAL CURRENTS IN GRANULAR SUPERCONDUCTORS

ABSTRACT . Disordered granular superconductors present one or more small resis- tivity peaks curves at lower temperatures than the critical one T c [1–9]. A model based on Josephson junctions array and Coulomb blockage capable to explain re- entrant resistive peaks in diamond-like carbon-silicon films containing tungsten was proposed by Chudinov et al. [10]. A computational method [11] developed ac- cording to such a model for the determination of superconducting percolation paths clearly showed their link to the peak-type re-entrant superconductivity [10]. Based on the same model and approach, a further method was developed to compute the critical current densities j c through simulated C—Si-–W granular superconduc- tors in the temperature region T ≤ T c . The strict correspondence of experimental and computed results [12] constituted a deeper confirmation of the validity of the proposed underlying physical model and its capability to describe richer, more structurated aspects of the re-entrant phenomenon.