Gast ::
| Hauptseite > Publikationsdatenbank > Meandering of the grain boundary and d-wave effects in high-Tc bicrystal Josephson junctions |
| Hauptseite > Publikationsdatenbank > Meandering of the grain boundary and d-wave effects in high-Tc bicrystal Josephson junctions |
| Journal Article | PreJuSER-49944 |
; ; ; ; ;
2006
IOP Publ.
Bristol
This record in other databases: 
Please use a persistent id in citations: doi:10.1088/0953-2048/19/5/S06
Abstract: We have produced submicrometre wide bicrystal Josephson junctions on the basis of YBa2Cu3O7-delta (YBCO) films and investigated their microstructure and superconducting properties. A 300 nm thick buffer layer of SrTiO3 on the SrTiO3 bicrystal substrates has helped to improve the quality and reproducibility of the junctions. The surface of the films at the grain boundary (GB) was investigated by high-resolution scanning electron microscopy (HRSEM). This has revealed one unit cell steps on the YBCO film surface and meandering of the GB in the YBCO film. Planar transmission electron microscopy investigations of the junction have confirmed that the GB in YBCO had a linear deviation from the underlying GB in the substrate up to similar to 0.4 mu m. The observed spread of the angles of the deviation of the GB in the film from the direction of the GB in the substrate on the slot- and other defect-free parts of the GB was below 10 degrees. Due to the d-wave symmetry of the order parameter in YBCO the reduction of the curvature of the GB leads to an improvement of the homogeneity of the current flow and a doubling of the critical current I-c of the junction. The observed IcRn product of symmetric 20 degrees bicrystal junctions was similar to 400 mu V at 77.4 K and similar to 1 mV at 63 K. Integration of such junctions in SQUIDs with a square 16 mm multilayer flux transformer has allowed us, for the first time, to reach a field resolution for the high-T-c magnetometers of similar to 3.5 fT Hz(-1/2) at 77.4 K.
Keyword(s): J
|
The record appears in these collections: |