New barriers for fast-switching SNS josephson junctions

We report recent results on the development of two different kinds of SNS Josephson junctions which can be used as quantum D/A converters. We have fabricated these devices using as a barrier either a thick 50-100 aluminum layer or a not-stabilized tantalum oxide layer. For both technologies we have determined the dependence of the main electrical properties of the junctions on the fabrication process. Measurements of the rf properties for the Nb/Al/Nb junctions and of the magnetical properties for the Nb/TaOx/Nb junctions are also reported.