The PI will prepare high-transition temperature superconductive films by deposition onto cooled substrates. Reactive sputtering and hot oxygen jet sputter fabrication techniques will be employed to produce as-deposited high-quality YBa2Cu3O7-x thin-films. After the initial investigation of the composition, microstructure and the DC electrical properties, these films will be patterned into variable thickness microbridges for millimeter-wave detection and mixing applications. Special emphasis will be given to the repeatability of the fabrication process as it applies to the transition temperature, critical current, and properties under radiation. In the second stage of the investigation, the microbridges will be used as heterodyne detectors in the millimeter-wave range. We have in our laboratories a good collection of active devices (sources, oscillators, detectors, mixers, isolators) and passive components in the 94 GHz range. The first goal will be to investigate the microwave properties of the microbridges by pumping with an rf source at this frequency. Then the microbridge will be operated as a mixer. The conversion efficiency, and mixer noise will be measured.
