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arXiv · 0812.4715

Flux quanta driven by high-density currents in low-impurity V3Si and LuNi2B2C: free flux flow and flux-core size effect

A. A. Gapud·S. Moraes·R. P. Khadka·P. C. Canfield·V. G. Kogan·A. P. Reyes·L. L. Lumata·D. K. Christen·J. R. Thompson
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Abstract

High density direct currents (DC) are used to drive flux quanta via the Lorentz force towards a highly ordered "free flux flow" (FFF) dynamic state, made possible by the weak-pinning environment of high-quality, single-crystal samples of two low-Tc superconducting compounds, V3Si and LuNi2B2C. We report the effect of the magnetic field-dependent fluxon core size on flux flow resistivity rho_f. Much progress has been made in minimizing the technical challenges associated with the use of high currents. Attainment of a FFF phase is indicated by the saturation at highest currents of flux-flow dissipation levels that are well below the normal state resistance and have field-dependent values. The field dependence of the corresponding rho_f is shown to be consistent with a prediction based on a model for the decrease of flux core size at higher fields in weak-coupling BCS s-wave materials.

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A. A. Gapud, S. Moraes, R. P. Khadka, P. C. Canfield, V. G. Kogan, A. P. Reyes, L. L. Lumata, D. K. Christen, J. R. Thompson. 2008-12-26. Flux quanta driven by high-density currents in low-impurity V3Si and LuNi2B2C: free flux flow and flux-core size effect. https://doi.org/10.1103/physrevb.80.134524

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