NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenF: Europan Campus Rottal-InnZeitschriftenartikel
B. Moenter, M. Getta, Sascha Kreiskott, H. Piel, N. Pupeter, Pouryamout, J.
High J/sub C/ YBCO films on biaxially textured Ni with oxide buffer layers deposited using evaporation and sputtering techniques
IEEE Transactions on Appiled Superconductivity, vol. 13, no. 2, pp. 2543-2546
2003
DOI: 10.1109/TASC.2003.811843
Abstract anzeigen
Epitaxial buffer layers of CeO/sub 2/ and Yttria-stabilized ZrO/sub 2/ (YSZ) have been deposited on biaxially textured nickel substrates using thermal reactive evaporation, electron beam evaporation and rf sputtering. The buffer layers were characterized by XRD, SEM and optical microscopy. YBCO films were deposited by high-pressure dc sputtering on CeO/sub 2//YSZ/CeO/sub 2/ buffered substrates and the resulting superconducting properties were measured inductively. On exclusively evaporated buffer architectures critical current densities of 0.6 MA/cm/sup 2/ (77 K, H = 0 T) were measured. The buffers showed some cracks after YBCO deposition, which we considered to be responsible for the relatively low J/sub c/. Buffer architectures with evaporated CeO/sub 2/ followed by rf sputtering of YSZ and CeO/sub 2/ in oxygen atmosphere remained completely crack free after YBCO deposition. Critical current densities between 1.5 and 2.3 MA/cm/sup 2/ (77 K, H = 0 T) in 460 nm thick YBCO films were obtained reproducibly. The critical temperatures T/sub c/ ranged between 88 and 92 K and the typical width /spl Delta/T/sub c/ of the transition was 1.5 K.
NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenF: Europan Campus Rottal-InnZeitschriftenartikel
Polak, M., Krempasky, L., Demencik, E., Wehler, D., Sascha Kreiskott, B. Mönter, Polyanskii, A., Larbalestier, D.C., B. Moenter
Critical currents of narrow YBCO rings on ni and LaAlO/sub 3/ substrates
IEEE Transactions on Appiled Superconductivity, vol. 13, no. 2, pp. 2595-2598
2003
DOI: 10.1109/TASC.2003.811857
Abstract anzeigen
Low loss YBCO based flexible conductors for AC operation must have a filamentary structure with filament width below 0.1 mm. MO images of structured YBCO films showed that the flux penetration is less homogeneous in YBCO filaments on Ni substrates than that in filaments on LaAlO, which indicates that the patterning may affect the critical current density in narrow filaments. To see the effect of patterning on the filament critical current we studied I-V curves and critical currents of YBCO rings with various widths ranging from 0.3 mm down to 0.02 mm. The rings were prepared by a standard lithographic process. To avoid problems with current contacts, the current in the rings was induced by external magnetic field and electric field-current characteristics were determined by a Hall probe method.
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