A Model Analysis for Current-Voltage Characteristics of Superconducting Weak Links

Abstract

A new phenomenological model for realizing the current-voltage ( I-V ) characteristics of superconducting weak links has been proposed and studied. In this model, the total bias current to the weak link is decomposed in two parts. One part obeys the usual resistively shunted junction (RSJ) type current-voltage relation, and the other obeys the flux-flow (FF) one. It has been shown that the fitting results of the I-V characteristics agree quite well to experimental data. The model and analysis method presented here is quite general, thus the model can be applied to other types of superconducting weak links for both high- and low-T c material.

Advantageous grain boundaries in iron pnictide superconductors

“…In general, the shapes of the I – V curves of BGB junctions depend on the fractions of the Josephson current exhibiting resistively shunted junction (RSJ) behaviour ( W RSJ ) and a supercurrent showing flux flow (FF) behaviour ( W FF ). A phenomenological model to explain their fractions in I – V curves was previously proposed as follows 28 : I – V curves are expressed by the combination of the RSJ and the FF behaviours, where the RSJ current follows and the FF current follows I FF = I S − A exp(− V / V 0 ) ( R N is the normal-state resistance of the barrier, and I S , A and V 0 are constants). The fitting results based on this model drawn by the blue lines reproduce the experimental I – V curves well.…”

“…The junction resistance R N A , where A is the cross-sectional area of the junction, provides information on the nature of the barrier in BGB junctions. The R N A products were estimated by fitting the above-mentioned model to the experimental I – V curves 28 . The R N A of the BaFe 2 As 2 :Co BGB junctions are 5×10 −11 Ωcm 2 for θ GB =16° and 5×10 −10 Ωcm 2 for θ GB =45°, which are one or two orders of magnitude smaller than those of the YBCO BGB junctions (6×10 −9 –8×10 −8 Ωcm 2 for θ GB =16°–45°, respectively).…”

Exploration of new superconductors and functional materials, and fabrication of superconducting tapes and wires of iron pnictides

“…Figure 87 shows the I – V curves for BGB junctions with θ GB = 16°, 24°, 30° and 45°. The dotted lines are the fits by the AH model, while the solid lines are fits by a phenomenological model previously proposed to explain the fractions of flux–flow and RSJ behaviors [436]. The latter fits indicate that the fractions of the RSJ current are approximately 70%, 90%, 100% and 100% for the BGB junctions with θ GB = 16°, 24°, 30° and 45°, respectively.…”

The simulation of current-voltage characteristics and the dynamic conductivity of the ballistic contacts based on superconductors with weak oscillation order parameter

“…Generally, experimenters often use resistive-shunted model (RSJ-model) [9,10], or its various modifications [11,12] to describe the main electrical characteristics of superconducting structures, consisting of a combination of superconductor (S) with normal metal (N), due to the simplicity of the mathematical apparatus, as existing microscopic theory for the considering superconducting structures are rarely used due to their complexity [13]. The RSJ-model takes into account the capacitive channel to describe the characteristics of the SIS-contact (Ssuperconductor, I -insulator) while for SNS-contact (Nnormal metal) the capacitive channel is not taken into account.…”