Electrical transport properties of Josephson junctions with a Nb/Au/PI(PbBi) structure

Abstract

We fabricated tunnel junctions with structures of Au/PI/Pb and of Nb/Au/PI/(PbBi) incorporating high-quality and ultrathin polyimide (PI) Langmuir-Blodgett (LB) films and then examined the electrical transport properties of the junctions. The inelastic electron tunneling spectroscopy (IETS) spectra of the Au/PI/Pb junctions reveals that the inelastic electron tunneling process accompanied by the energy loss due to the coupling of tunneling electrons with the vibrational modes of polyimide does not make a significant contribution. For Nb/Au/PI/(PbBi) Josephson junctions, we obtained typical I-V characteristics of a weakly coupled superconductor. © 1992.