We have grown crystalline thin films of LaAlO3 using off-axis rf sputtering from a single stoichiometric target. The films grow epitaxially on SrTiO3 and LaAlO3  (100) substrates as well as on YBa2Cu3O7 thin films. We report on the growth conditions used to make these films, the properties of the films, and the properties of bilayer and trilayer structures containing both LaAlO3 and YBa2Cu3O7 films. Transmission electron microscopy cross-sectional and x-ray diffraction analyses indicate that all the constituent films in the multilayers grow epitaxially and that the interfaces between the films are sharply defined. Preliminary transport measurements on these multilayers show that LaAlO3 can be used for dielectric layers in a variety of high-temperature superconductor electronic circuits.

We have developed a technique which permits high-yield fabrication of microbridges and low noise YBa2Cu3O7 superconducting quantum interference devices (SQUIDs) in epitaxial thin films. These SQUIDs operate over a wide temperature range extending from 4 K to close to the superconducting transition temperature. Measurements of an rf SQUID operating at 77 K give a peak-to-peak flux sensitivity of 36 μV/Φ0 and a flux noise at 10 Hz of 1.5× 10−4 Φ0/√Hz. Device yields over 80% have been obtained.

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Step-edge Josephson junctions are engineered grain boundary junctions fabricated using standard lithographic and film deposition techniques. We report a systematic study of 180 YBa2Cu3O7 step-edge junctions and identify a fabrication technique which results in a 90% yield of working junctions with critical current spreads from 30% to 50% (1σ/Ic-ave)over the entire substrate. Technically useful critical current values at 65 K can be obtained by adjusting YBa2Cu3O7 film thickness. IcRn values, approximately independent of film thickness, are ∼1 mV at 4.2 K and ∼0.1 mV at 65 K. Most junctions exhibit ideal electrical behavior in accordance with the RSJ model.

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