YBa2Cu3O7-δ α-Axis Films and Planar Junctions

Ronald G. Wichern, Eugène M.C.M. Reuvekamp, Gerrit J. Gerritsma, Horst Rogalla

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Abstract

In order to prepare planar junctions, multilayers were sputtered, using YBa2Cu3O7-δ as superconductor and PrBa2Cu3O7-δ as barrier material. The sandwiches are a-axis oriented. Out of these, single junctions were etched, planarized with CeO2. Finally gold contacts were sputtered. The junctions are squares of size 20x20 to 100x100 μm2. A prerequisite for successful preparation of junctions from a-axis oriented multilayers is a study of such films. Films deposited by RF off-axis sputtering were characterized electrically, Their morphology was investigated by XRD, AFM and TEM. The films are very smooth and have a grain size of below 100x100 nm2. To improve Tc and crystal quality, template layers were used. The Tc of a single film is about 62 K; by using a template layer up to 78 K can be reached. For α-axis oriented growth not only a reduction of the deposition temperature is important, but also the growth rate must be high enough. Best results were obtained at rates higher than 150 nm/h. The first planar junctions show a supercurrent, but otherwise rounded I-V curves.
Original languageEnglish
Pages (from-to)2361-2364
Number of pages4
JournalIEEE transactions on applied superconductivity
Volume5
Issue number2
DOIs
Publication statusPublished - 1995

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Wichern, R. G., Reuvekamp, E. M. C. M., Gerritsma, G. J., & Rogalla, H. (1995). YBa2Cu3O7-δ α-Axis Films and Planar Junctions. IEEE transactions on applied superconductivity, 5(2), 2361-2364. https://doi.org/10.1109/77.403060