Dresden 2006 – scientific programme

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TT: Tiefe Temperaturen

TT 33: Superconductivity: Vortex Dynamics, Vortex Phases, Pinning

TT 33.3: Talk

Friday, March 31, 2006, 10:45–11:00, HSZ 304

Nonlocal Vortex Dynamics in Narrow Superconducting Channels — •Andreas Helzel¹, Ivan Kokanović², Dinko Babić², and Christoph Strunk¹ — ¹Institut für experimentelle und angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany — ²Department of Physics, Faculty of Science, University of Zagreb, Bijenička 32, HR-10000 Zagreb, Croatia

We investigated superconducting microstructures composed of a vertical wire crossed by two horizontal wires. In presence of an external magnetic field, a supercurrent in the upper horizontal wire drives a flow of vortices in the vertical wire. This results in a nonlocal voltage response in the lower wire [1]. We use very low pinning amorphous NbGe as superconductor, resulting in a 100 times larger nonlocal response compared to [1] and a moderate decrease when varying the channel length between 2 and 5 µ m. Comparing with the local flux flow properties, we observe that the nonlocal flux flow is maximal around the irreversibility line of plain NbGe wires and extends up to B_c2. In the regime of very few vortex rows in the channel reproducible fluctuations occur in the nonlocal signal, which can be understood as jamming effects near the detector cross.

[1] Grigorieva et. al., Phys. Rev. Lett. 92, 237001 (2004)