Electronic Resource
Woodbury, NY
:
American Institute of Physics (AIP)
Applied Physics Letters
65 (1994), S. 112-114
ISSN:
1077-3118
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The gap voltage of Nb-Al/AlOx-Nb junctions was studied as a function of the Nb electrode thickness. The gap parameter increased with the electrode thickness. The I(V) curves of these junctions, employed as quasiparticle frequency mixers, are discussed. For 120-nm-thick Nb electrodes, a gap voltage 2Δ/e of 2.95 mV at 3 K is found in junctions with a critical current density of 2.5 kA/cm2. This is close to the ideal bulk value of Nb. The corresponding gap frequency of 714 GHz is clearly above 691 GHz, an important radioastronomical frequency. Complementary Tc measurements of Nb films have been carried out. The results agree with a model based on the proximity effect between the ideal metallic layer and a nonideal surface layer.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.113051
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