Current and voltage distribution in composite superconductors with resistive barriers - asymmetric case

An equivalent asymmetric scheme with distributed parameters is proposed and is aimed at simulating the current and voltage distributions in composite high-Tc superconductors with thin resistive barriers around the filaments. There are three longitudinal parallel branches in the scheme, representing the superconducting core, the metallic inner matrix around this core and the outer metallic matrix. The transversal current flow is controlled by two interlayer elements: one represents the barrier inserted between the outer and inner Ag matrices, while the second simulates the interface resistance between the inner Ag matrix and the superconducting Bi-2223 core. The superconducting core may be completely without resistance, but it can be found eventually in the resistive state. In this paper, referring to our previous paper, we deal with the case when the transport current is supplied to the composite conductor through the outer Ag matrix and leaves via the superconducting Bi-2223 core with removed outer Ag matrix and resistive barrier. The current is forced to pass transversally through the barrier. The current and voltage distributions along the conductor section followed are mainly governed by the properties of the resistive barrier. In this way, the properties of the barrier can be reliably determined. The governing relation in the scheme is the product of the matrix-superconductor interface conductance and of the inner matrix resistance per unit length. The solution of the scheme leads to results that depend on the following dimensionless relations: the ratio of the barrier to the matrix-superconductor interface conductances per unit length, the ratio of the outer to the inner matrices resistances per unit length and the ratio of the core resistance to the inner matrix resistance per unit length. (author)