Electrodynamic Study of Josephson Tunneling in Superconducting Junctions

Abstract

We have performed a quantitative electrodynamic experiment on a Josephson oxide tunneling junction. Using a current source at 30 Mc/sec, we have verified the time dependence of the Josephson equation, $j=j_0$ $sin [{\gamma }_l-{\gamma }_r-(\frac{2e}{\hslash }\left)\int \mathrm{A}·\mathrm{dl}\right]$, where $\left(\frac{\partial }{\partial t}\right)[{\gamma }_l-{\gamma }_r-(\frac{2e}{\hslash }\left)\int l^r\mathrm{A}·\mathrm{dl}\right]=-\left(\frac{2eV}{\hslash }\right)$. Thus the limiting voltage is shown to obey the quantum relationship relationship, $2eV=\hslash \omega$. Measurements were made completely in the coherent state showing the diffraction nature of the junction as a function of applied magnetic field. The Josephson (parametric) inductance of the junction was directly observed and is in good agreement with the theory.