Globalisierung des Marketing bei internationaler Unternehmenstaetigkeit

Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel C 175123 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Erfolgswirkungen der internationalen Marketingstandardisierung

Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel C 200699 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Globale Wettbewerbsstrategien und laenderuebergreifende Integration: Status und Entwicklungsperspektiven

Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel C 182011 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Magnetic instability in YBa2Cu307-delta films

Using a magneto-optic technique we have investigated the magnetic flux propagation into and out of superconducting thin YBa2Cu3O7-b films. After field cooling below Tc, the external magnetic field Bext perpendicular to the film is changed which gives rise to shielding currents in the sample. The current distribution is disturbed momentarily by heating with a focused laser pulse near the sample edge. This triggers a magnetic instability, in which a magnetic flux avalance starts to propagate

Reversible laser annealing and magneto-optical characterization of HTSC thin films

The oxygen content in YBCO thin films can be changed locally by scanning a focused laser beam across the film surface at defined oxygen partial pressure. In contrast to annealing experiments in a furnace where the oxygen concentration remains homogeneous in the direction of the film layer, the local heating with a laser beam leads also to a lateral oxygen diffusion in the thin film. By investigating the laser written structures a deeper understanding of the patterning process itself and the oxygen diffusion in YBCO thin films could be obtained. For the detection of laser written structures and natural defects in HTSC thin films the magneto-optical method is highly qualified. It allows to visualize the magnetic screening behaviour with a high lateral resolution in the range of micrometers. In the past this technique was used to investigate the magnetic flux distribution in smaller samples at temperatures far below the boiling point of liquid nitrogen. In this work the magnetic resolution of the method was optimized so that much weaker magnetic field contrasts at 77 K can still be detected. In particular the presented apparatus allows the characterization of double-sided 3" HTSC Wafers even under conditions where cooling with liquid helium or closed-cycle refrigerators is not available

Magneto-Optic Characterization of Defects and Study of Flux Avalanches in High-Tc Superconductors down to Nanosecond Time Resolution

Optical methods offer an intrinsic high potential for experiments with excellent spatial and in particular also temporal resolution. Using the Faraday effect we carried out magneto-optical investigations of high-Tc superconductor thin films in a polarization microscope. Small defects in the superconducting material which possess a lower critical current density disturb the homogeneous penetration of magnetic flux into a sample when an external magnetic field is applied after zero field cooling. This is true even if the defects are below the sample surface or when the superconducting sample is covered by a thin layer of another material, e.g., gold, and can be used to characterize samples with diameters up to 3". For studies of the dynamics of magnetic flux in a superconducting sample, a pump-probe setup has been used. An instability which causes magnetic flux to enter the sample in dendritic form [1] is triggered by local heating with a focused ns or fs laser pulse. Part of the beam is separated by a beam splitter, passed through a variable delay line of suitable length and used for illumination of the sample. ForYBa2Cu307- 6 thin films a spreading velocity of (5 + 2) x 1o4 m/s is found which is an order of magnitude higher than the velocity of sound. The total area of the dendritic structure formed is found to depend linearly on the change Bext of the external magnetic flux density applied before the trigger pulse. No dependence on the pulse duration has been observed, suggesting a purely thermal nature of the trigger process

Zerstörungsfreie magnetooptische Charakterisierung von natürlichen und künstlichen Defekten an 3-Zoll-HTSL-Wafern bei 77K

Doppelsei tige 3-Zoll-HTSL-Wafer wurden magnetooptisch charakterisiert. Der vorgestellte Aufbau erlaubt einen schnellen und zerstorungsfreien Nachweis von lokalen und ausgedehnten Inhornogenitiiten in der kritischen Stromdichte rnit hoher Ortsauflosung im Mikrometerbereich. Zusatzliche Goldschichten auf den HTSL-Wafem, wie sie manchmal in der Bauteilherstellung eingesetzt werden, beeinflussen nicht das Ergebnis der Messungen. Die hohe rnagnetische Empfindlichkeit erlaubt sogar den Nachweis lokaler Defekte bei 77 K, wo der Kontrast in den kntischen Stromen schwiicher ist und die Charakterisierung von HTSLFilmen vie1 schwieriger ist als bei tieferen Temperaturen. Der Aufbau kann daher selbst unter Bedjngungen eingesetzt werden, bei denen Kiihlung rnittels Flussig-Helium oder Kleinkuhler nicht zur Verfugung steht. Die Empfindljchkeit wurde an natiirlichen und lainstlichen Defekten iiberpriift, wobei letztere durch fokussierte Laserstrahlung hergestellt wurden