Josephson tunnel junctions with monomolecular barriers

We report here the fabrication of Josephson junction tunnel diodes in which the barrier has been deposited using the Langmuir-Blodgett technique. Diodes have been fabricated using lead-indium alloys and niobium nitride for the electrodes. The barrier was vinyl stearate polymerized by Co60γ radiation just prior to depositing the counter electrode. We have obtained critical current densities from 100-820 amps/cm2at 4.2°K, and we have observed hysteretic behavior. Preliminary measurements of the dependence of the critical current on the applied magnetic field have also been made.