We present a new experiment on YBa2Cu3O7−x thin films using spatially resolved heavy ion irradiation. Structures consisting of a periodic array of strong and weak pinning channels were created with the help of metal masks. The channels formed an angle of ±45• with respect to the symmetry axis of the photolithographically patterned structures. Investigations of the anisotropic transport properties of these structures were performed. We found striking resemblance to guided vortex motion as it was observed in YBa2Cu3O7−x single crystals containing an array of unidirected twin boundaries. The use of two additional test bridges allowed to determine in parallel the resistivities of the irradiated and unirradiated parts as well as the respective current-voltage characteristics. These measurements provided the input parameters for a numerical simulation of the potential distribution of the Hall patterning. In contrast to the unidirected twin boundaries in our experiment both strong and weak pinning regions are spatially extended. The interfaces between unirradiated and irradiated regions therefore form a Bose-glass contact. The experimentally observed magnetic field dependence of the transverse voltage vanishes faster than expected from the numerical simulation and we interpret this as a hydrodynamical interaction between a Bose-glass phase and a vortex liquid.

A detailed analysis of the electric field-current density (EϪJ) characteristics of YBa 2 Cu 3 O 7Ϫ␦ films across the putative thermally induced elastic vortex-glass-vortex-liquid transition predicted by the E(J) curve scaling reveals that the expected increase of the collective pinning barriers with decreasing J is cut off in the low-J region, signaling a dissipation process which involves the plastic deformation of the vortex system. The temperature and magnetic field dependence of the pinning barriers at low J does not change across the scaling-predicted glass transition line. For the investigated magnetic field range ͑0.5-7 T͒, over a relatively large temperature interval, in YBa 2 Cu 3 O 7Ϫ␦ films there appears a continuous crossover in a pinned plastic vortex assembly, rather than a thermally induced elastic vortex-glass-vortex-liquid transition.

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We investigated the current-voltage (I-V) curves of high-Ta superconductors at very low and very high dissipation levels. In the limit of low driving currents the barriers for vortex movement become infinite in the vortex-glass state. Using long measurement bridges up to 0.5 m we were able to sample an electric field range from 1 V/rn down to 1O_8 V/rn in one experimental setup. The resulting I-V curves allowed us to verify an excellent glass scaling of the I-v curves, which revealed an increased dynamical exponent of the glass transition. We also found a considerable dependence of the vortex-glass scaling on the probed electric-field range. At very high dissipation levels the I-V curves of type II superconductors in magnetic fields can show voltage jumps due to flux-flow instabilities at high vortex-velocities. They have been investigated in Bi2Sr2CaCu2O8 and YBa2Cu3O7. The results have been interpreted in the framework of the theory of Larkin and Ovchinnikov. The extensions introduced by Bezugly and Shklovskij account for unavoidable quasiparticle heating during the measurement. The influence of avoidable heating effects on the I-V curves was studied experimentally by pulsed measurements with a time resolution in the microsecond range. In Bi2Sr2CaCu2O8 we found the instability in the vortex-liquid phase. However, in YBa2Cu3O7 a remarkable coincidence between the vortex-glass phase, which manifests itself at low dissipation, and the existence of the high dissipative flux-flow instability was observed.