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arXiv · 0708.2602

Negative magnetoresistance of ultra-narrow superconducting nanowires in the resistive state

K. Yu. Arutyunov
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Abstract

We present a phenomenological model qualitatively explaining negative magnetoresistance in quasi-one-dimensional superconducting channels in the resistive state. The model is based on the assumption that fluctuations of the order parameter (phase slips) are responsible for the finite effective resistance of a narrow superconducting wire sufficiently close to the critical temperature. Each fluctuation is accompanied by an instant formation of a quasi-normal region of the order of the non-equilibrium quasiparticle relaxation length 'pinned' to the core of the phase slip. The effective time-averaged voltage measured in experiment is a sum of two terms. First one is the conventional contribution linked to the rate of the fluctuations via the Josephson relation. Second term is the Ohmic contribution of this quasi-normal region. Depending on material properties of the wire, there might be a range of magnetic fields where the first term is not much affected, while the second term is effectively suppressed contributing to the experimentally observed negative magnetoresistance.

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K. Yu. Arutyunov. 2007-08-22. Negative magnetoresistance of ultra-narrow superconducting nanowires in the resistive state. https://doi.org/10.1016/j.physc.2007.08.027

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