This Small Business Innovation Research Phase I project will develop and evaluate independent strategies for extending operating lifetimes of SQUlDs fabricated from YBa2Cu307-( step-edge junctions. Two strategies will be evaluated in Phase 1. The first strategy is to find a coating that is suitable for protecting Josephson junctions and is compatible with `flip chip` technology. The second approach is to fabricate step-edge junctions from the corrosion resistant phase of Yl-xCaxBa2-yLayCu3O7-( and Gdl-xCaxBa2LayCu3O7-( compounds. Corrosion is particularly problematic during the fabrication and operation of step-edge Josephson junctions and the strategies developed in this work will be applicable to a large range of devices fabricated from cuprate superconductors. One of the most serious problems that has limited the commercialization of YBa2Cu307-( devices are their lack of environmental stability. The cuprate superconductor YBa2Cu307-( tends to degrade rapidly when exposed to the ambient atmosphere through corrosion reactions caused by H20 and CO2. These corrosion problems severely limit the lifetimes of electronic devices fabricated from YBa2Cu307-(. The current generation of cuprate based devices are very susceptible to corrosion and have a very limited lifetime. The proposed research is intended to lead to new technologies for the fabrication of robust superconducting electronics. These devices may find application in a number of diverse areas such as MRI, NMR, magnetic sensing, and low noise electronics.
