engleski

Transversal Flux-Transformer Effect in Narrow Superconducting Channels of a-Nb0.7Ge0.3

We study nonlocal vortex transport in mesoscopic amorphous Nb0.7Ge0.3 samples. A dc current I is passed through a wire connected via a perpendicular channel, of a length L = 2 - 5 mikro metra and width w = 0.1 - 2 mikro metra, with a pair of voltage probes where a nonlocal response Vnl/I is measured. In our low-pinning a-Nb0.7Ge0.3, the effect appears in more than half of the superconducting phase diagram, i.e. everywhere where the vortices can be moved easily enough to induce dissipation at very low currents. The maximum of Rnl = Vnl/I for a given temperature occurs at an L-independent magnetic field and is proportional to 1/L. The influence of the vortex-matter viscosity alone is more easily studied in the limit T->Tc, where pinning effects are negligible. We present a detailed study of the T- and w-dependence of the effect.

vortex transport; amorphous Nb0.7Ge0.3

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