Subharmonic Structure in Pb-Pb Superconductive Tunneling Junctions

The Detection of Alpha Particles With Superconducting Tunnel Junctions

“…in the range 10<B <1 <100 G. The conclusion that Marcus draws from this evidence, in contradiction to Yanson et al, is that the 2A/n singularities are due to a tunneling process taking place in the region of the junction where the metallic filaments exist. Zawadowski (1966), on the other hand, interprets the data of Rochlin and Douglass (1966), who observed several series of 2A/n singularities in Pb-Pb junctions, as being due to the break up of P pairs and the subsequent tunneling or transition through metallic filaments of n electrons in the same higher order quantum mechanical processes with a voltage threshold 2AP/n. Taking appropriate values of P and n, he was able to fit all the singularities observed by Rochlin and Douglass. Still another explanation of the subharmonic tunneling phenomenon is suggested by Zawadowski in the same paper.…”

New Measurements of the Electromagnetic Absorption Spectrum of Superconducting Lead

“…Note also that the absorption edge seems fairly smooth, with no clear evidence for additional absorption edges arising from critical gaps. 2 It therefore seems likely that the excess absorption above the main edge previously reported by us was also due to the presence of higher order radiation. We believe that in our earlier work, higher order radiation diffracted out of the monochromator beam by a transmission filter grating was nevertheless able to reach the sample, presumably after undergoing a reflection not allowed for in our original design of the opti- The absorption below the main edge in superconducting lead previously reported was found to have been instrumental in origin, and does not appear in more recent data.…”

Tunneling at Point Contacts between Superconductors

“…8 A weak link biased to a finite voltage and thus supporting an ac supercurrent not only emits radiation but also is very sensitive to radiation from an external source. 4,5 The electromagnetic field of the external radiation evidently modulates the voltage across the junction, which in turn frequency-modulates the ac supercurrent. 4 This modulation creates sidebands at *>o=b«j>, where vo is the undisturbed frequency of the supercurrent (vo=2eVo/h), v is the frequency of the external radiation, and n is an integer.…”