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.