Regensburg 1998 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 8: Josephson-Kontakte
TT 8.1: Hauptvortrag
Dienstag, 24. März 1998, 09:30–10:00, H 20
Cherenkov radiation from Josephson fluxons — •A. V. Ustinov1, E. Goldobin2, G. Hechtfischer1, N. Thyssen2, A. Wallraff1, R. Kleiner1, and P. M"uller1 — 1Physikalisches Institut III, Universit"at Erlangen-N"urnberg, Erwin-Rommel-Str. 1, D-91058 Erlangen — 2Institut f"ur Schicht- und Ionentechnik, Forschungszentrum J"ulich, D-52425 J"ulich
Observations of Cherenkov radiation by Josephson vortices (fluxons) moving in multilayer tunnel junctions will be presented. Experiments are made with two different superconducting systems, namely artificially prepared Nb-AlOx-Nb stacks [1] and naturally layered BSCCO crystals [2]. In the first case, Cherenkov radiation in two stacked annular Josephson junctions leads to resonances which result from interaction of Cherenkov radiation wake with a Josephson vortex turning around the junction. Experimental data are in good quantitative agreement with the proposed model, excellent agreement with numerical simulations is also found. In the second case, large number of wave propagation modes (equal to the number of intrinsically stacked junctions) leads to a broad band non-Josephson emission which has been detected experimentally. Reported results suggest rather unusual fluxon dynamics in intrinsic junctions of high temperature superconductors.
[1] E. Goldobin et al., Phys. Rev. B 56, December 1 issue (1997)
[2] G. Hechtfischer et al., Phys. Rev. Lett. 79, 1365 (1997)