Randy Wayne Simon

Multisource-sputtered ErBa2Cu3O7−x films on single-crystal and buffered crystalline substrates

High-quality superconducting films of erbium-barium-copper-oxide have been produced in a multisource sputtering system on a variety of substrates, including buffered sapphire and silicon wafers as well as various single-crystal materials. Fine-grained polycrystalline films with narrow (<4 K) resistive transitions have been grown on a number of different substrates. The use of erbium in the 12–3 compound leads to improved film morphology and to more forgiving conditions for establishing of the superconducting phase. Sputtered neutral mass spectroscopy (SNMS) yields useful information about the compositional profile of the films.

High-temperature superconducting Josephson junction devices

The reasons for the failure to develop a successful Josephson tunnel junction made from high-temperature superconducting cuprates is discussed. The difficulties in developing a theoretical analysis of even simple-to-make cuprate Josephson devices are pointed out. The development of alternative Josephson devices based on the fabrication of engineered microbridges is addressed, and an overview is given of successful YBCO microbridges. Emphasis is given to focused ion beam and step-edge microbridges.