Regensburg 2000 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 12: Fachsymposium: Korngrenzen in HTSL
TT 12.2: Hauptvortrag
Dienstag, 28. März 2000, 15:00–15:30, H18
Understanding and adjusting basic properties of grain boundaries in high-Tc superconductors — •H. Hilgenkamp1,2, B. Goetz1, R.R. Schulz1, C.W. Schneider1, B. Chesca1, H. Bielefeldt1, A. Schmehl1, and J. Mannhart1 — 1Exp. Phys. VI, EKM, Augsburg University, 86135 Augsburg — 2Appl. Phys. Dept., University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
Grain boundaries play a crucial role in many applications of high-Tc superconductors. Therefore, the understanding and control of their transport properties is of great relevance. Based on considerations of the microstructure, we have recently discussed the important roles of band-bending and the accompanying formation of space-charge layers, and of the predominant dx2−y2 -symmetry of the order parameter [1]. Experiments will be discussed, which were aimed to reduce the detrimental effects of band-bending at the interface, and have lead to the successful results of strong enhancements of the critical current density and reductions of the interface resistivity [2].
In the presentation we will furthermore discuss fabrication and measurements of an all high-Tc dc π superconducting quantum interference device (dc π-SQUID), realized in thin film technology on a tetracrystalline substrate [3]. This device, utilizing the unconventional order parameter symmetry, contains a standard junction and a junction with a π-phase shift.
[1] H. Hilgenkamp and J. Mannhart, Appl. Phys. Lett. 73, 265 (1998)
[2] A. Schmehl et al., Europhys. Lett. 47, 110 (1999)
[3] R.R. Schulz et al., Appl. Phys. Lett., in press