An experimental investigation has indicated that the egr;hyphen;phase Pbhyphen;Bi alloy is an attractive alternative to Pbndash;1.7 wt.percnt;thinsp;Au for use as a counterelectrode for Josephson tunneling devices containing Pbndash;12 wt.percnt;thinsp;Inndash;4 wt.percnt;thinsp;Au alloy films as base electrodes and control lines. Use of this Pbhyphen;Bi alloy as a counterelectrode results in a significant improvement in junction quality; the normalized subgap singlehyphen;particle tunneling current is sim;2times; lower at 2 mV. In addition, devices with the Pbhyphen;Bi counterelectrodes exhibit sim;3times; fewer failures after repeated thermal cycling between 300 and 4.2thinsp;deg;K. Out ot a total of 72 such devices having large area (6.2times;10minus;6cm2) junctions, 94percnt; survived 1000 thermal cycles with negligible change.
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