Large Josephson tunnel junctions have been fabricated using the dc plasma anodization method and their basic properties have been studied by the comparison between theory and experiment. It is shown that the uniformity of the tunneling barrier layer can be evaluated by the quasi-particle tunneling current and the magnetic field dependence of the maximum zero-voltage current. Many interesting phenomena have been observed in dc currentvoltage characteristics of large Josephson junctions in the

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... sence of a microwave radiation, and it is shown that they result from vortex motion induced by the applied microwave.