Electrical properties of a normal contact to HTSC Josephson media

Electrical properties of normal metal contacts to percolation Josephson HTSC systems are studied by computer simulation. The current and voltage distributions, current-voltage characteristics (IVC), and temperature dependences R-c(T) of the resistance of the Josephson network with a limited contact are calculated, ht is shown that macroheterogeneity of current distribution leads to broadening of the IVC and R-c(T) dependences of the contact in comparison with the bulk characteristics. In the vicinity of critical currents and temperatures, the contact IVC and R-c(T) obey the "3/2" law. A peak on the current and temperature dependences of the spreading resistance is observed. The applicability of the effective medium model for describing contact characteristics of the Josephson network is substantiated. The computer simulation results are in accord with experimental temperature dependences of the contact resistance. (C) 1998 American Institute of Physics.