Two-dimensional arrays of Josephson weak links

Two-dimensional arrays of Josephson weak links can be produced by evaporating metals in air or argon at reduced pressures onto insulating substrates. Below the superconducting transition temperature of the metal, these arrays enter a coherent state, capable of carrying a maximum supercurrent Ic, which has a temperature dependence similar to that for a single oxide barrier tunneling junction. The multiply connected nature of the arrays is most clearly demonstrated by a multiply periodic dependence of Ic on magnetic field applied perpendicular to the array. A simple model for the arrays with m current paths in parallel with n Josephson weak links in series is proposed. This model is used as a basis of a computer program which generates detailed I(V) curves for several assumed probability distributions of critical currents and two current-voltage characteristics for the individual weak links in the array. These computer-generated curves are compared with experiment. The model is also used to explain other aspects of the experimental observations, such as why the outermost current paths do not screen the applied magnetic field from inner paths. Some experimental results on the interaction of the arrays with electromagnetic radiation in the far infrared and microwave regions are included.