engleski

Static and time-resolved vortex dynamics in a- Nb0.7Ge0.3

We investigate the motion of vortices in amorphous Nb0.7Ge0.3. Because of the very low pinning in this high-kappa type-II superconductor, we are able to measure local and non-local transport in the flux-flow regime over large parts of the B-T-phase diagram [1]. Interestingly, there is a finite non-local response close to Tc, even when the applied magnetic field is zero. This points towards the presence of spontaneously formed vortex- antivortex pairs above the Berezinskii- Kosterlitz-Thouless transition. In addition, we report first non-local transport measurements in the time domain, using a boxcar averaging technique. [1] A.Helzel et al., Phys. Rev. B 74, 220510 (R) (2006)

superconductivity; vortices; pinning

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