Search results for "Superconducting wire"
showing 5 items of 5 documents
Tunable coaxial cavity resonator for linear and nonlinear microwave characterization of superconducting wires
2011
We discuss experimental results obtained using a tunable cylindrical coaxial cavity constituted by an outer Cu cylinder and an inner Pb-BSCCO wire. We have used this device for investigating the microwave response of the superconducting wire, both in the linear and nonlinear regimes. In particular, by tuning the different modes of the cavity to make them resonant at exactly harmonic frequencies, we have detected the power emitted by the superconducting inner wire at the second- and third-harmonic frequency of the driving field. The results obtained in the nonlinear regime, whether for the microwave surface impedance or the harmonic emission, are qualitatively accounted for considering inter…
Negative magnetoresistance of ultra-narrow superconducting nanowires in the resistive state
2008
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 contributio…
Coherent quantum phase slip
2012
A hundred years after discovery of superconductivity, one fundamental prediction of the theory, the coherent quantum phase slip (CQPS), has not been observed. CQPS is a phenomenon exactly dual to the Josephson effect: whilst the latter is a coherent transfer of charges between superconducting contacts, the former is a coherent transfer of vortices or fluxes across a superconducting wire. In contrast to previously reported observations of incoherent phase slip, the CQPS has been only a subject of theoretical study. Its experimental demonstration is made difficult by quasiparticle dissipation due to gapless excitations in nanowires or in vortex cores. This difficulty might be overcome by usin…
Phase Slip Phenomena in Ultra-Thin Superconducting Wires
2006
We present results on phase-slip phenomena in a superconducting wire which can be considered as quasi-one dimensional (1D) if its characteristic transverse dimension \( \sqrt \sigma\) (√ being the cross section) is smaller than the coherence length Λ(T). The shape of the bottom part of the resistive transition R(T) of a 1D superconducting strip is described by the model of phase slips activation. If the wire is infinitely long, then there is always a finite probability that a small part of the sample is instantly driven normal.
Long-range spin accumulation from heat injection in mesoscopic superconductors with Zeeman splitting
2015
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