Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 32: Postersession Superconductivity: Josephson Junctions, SQUIDs, Heterostructures, Andreev Scattering, Vortex Physics, Cryodetectors, Measuring Devices, Cryotechnique
TT 32.8: Poster
Mittwoch, 25. März 2009, 14:00–18:00, P1A
Investigation of superconducting thin film structures prepared by nanoscale wedge polishing — •Martin Pollithy1, Katharina Höfer1, Uwe Schinkel1, Peter Michalowski1, Veit Grosse1, Frank Schmidl1, Paul Seidel1, Dagmar Meier2, and Tanya Shapoval2 — 1FSU Jena, Institute of Solid State Physics, Helmholtzweg 5, D-07743 Jena, Germany — 2IFW Dresden, Institute for Metallic Materials, PO Box 270116, D-01171 Dresden, Germany
The performance of dc-SQUID gradiometers depends very strong on the spread of the critical parameters Ic, Rn and Ls. After the preparation of high temperature superconducting devices it could be useful to tune the superconducting properties by decrease of the film thickness. On the other hand it is often helpful for sensor applications to realise a superconducting thin film structure with a smooth surface to avoid resistive or superconducting shunts in insulating layers on the top of the superconductor. In these investigations we use a mechanical wedge polishing procedure [1] to thin the superconducting devices (microbridges, dc-SQUIDs or dc-SQUID gradiometers) before and/or after the first measurements of the electrical properties. AFM and SEM measurements were done to characterise the film morphology. Temperature dependent measurements of the superconducting properties of microbridges, dc-SQUIDs and dc-SQUID gradiometer structures were realised. We discuss the possibilities and limitations of this procedure.
[1] T.Shapoval, S.Engel, M.Gründlich, D.Meier, E.Backen, V.Neu, B.Holzapfel, L.Schultz, Supercond. Sci. Tech. 21 (2008) 105015