Dresden 2003 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 20: Postersitzung IV (Mesoskopische Systeme, Supraleitung: Massivmaterialien, Bandleiter, Pinning, Vortexdynamik, Transporteigenschaften, Korngrenzen)
TT 20.33: Poster
Donnerstag, 27. März 2003, 14:30–19:00, P2c, P2d
Experiments on individually superconducting CuO2 double layers in Bi2Sr2CaCu2O8+x — •Christoph Back, Michael Mößle, Paul Popovich, Dieter Koelle, and Reinhold Kleiner — Universität Tübingen, Physikalisches Institut - Experimentalphysik II, Auf der Morgenstelle 14, 72076 Tübingen
The critical temperature of the high temperature superconductor Bi2Sr2CaCu2O8+x (BSCCO) strongly depends on the carrier concentration, which is controlled by the oxygen content x. This fact allows to realize an ultrathin superconducting layer near the surface of an overdoped BSCCO single crystal by strongly reducing the oxygen content of its surface layers. If the gradient in oxygen concentration is strong enough this layer is as thin as only a few CuO2 double layers. Oxygen reduction of the outermost layers was achieved by heating the freshly cleaved crystal surface in vacuum. In order to perform electrical transport measurements with current flow along the superconducting layers four Ag electrodes were evaporated on the crystal surface. Above the critical temperature of the overdoped bulk crystal a very thin layer with a Tc up to 90 K is superconducting. Further analysis of the IV-characteristics shows that this layer consists of a few Josephson-coupled CuO2 double layers. We discuss flux dynamics of this coupled layers in magnetic fields up to 3 T and various orientations of the magnetic field.