Investigation of the superconducting proximity effect by Josephson tunneling

Abstract

Josephson junctions have been made with a superconductor on one side of the oxide and with a normal–superconducting (N–S) sandwich on the other side. Measurements of the temperature dependence of the maximum DC Josephson current have been taken.A simple model is proposed for the order parameters within the N–S system. Within the superconducting layer of this system the linear Ginzburg–Landau equation is used to describe the behavior of the order parameter. Within the normal metal, Werthamer's solution is used. Application of de Gennes' boundary conditions completes the determination of the order parameter. Josephson currents are calculated by using the de Gennes formulation. Agreement between experiment and theory has been obtained.