Potential and current distribution in strongly anisotropic Bi(2)Sr(2) CaCu(2)O(8) single crystals at current breakdown

TL;DR

This study investigates how current distributes and causes breakdown in anisotropic Bi(2)Sr(2)CaCu(2)O(8) superconductors, revealing a resistive front that depends on current magnitude and anisotropy effects.

Contribution

It introduces a novel in-depth voltage probe to measure the resistive region and demonstrates how anisotropy influences current penetration and breakdown patterns in BSCCO.

Findings

Resistive/nonresistive front moves outward with increasing current.

Resistive region depth is measured using a new in-depth voltage probe.

Current penetration is limited by anisotropy, causing a flat resistive region.

Abstract

Experiments on potential differences in the low-temperature vortex solid phase of monocrystalline platelets of superconducting Bi(2)Sr(2)CaCu(2)O(8) (BSCCO) subjected to currents driven either through an "ab" surface or from one such surface to another show evidence of a resistive/nonresistive front moving progressively out from the current contacts as the current increases. The depth of the resistive region has been measured by a novel in-depth voltage probe contact. The position of the front associated with an injection point appears to depend only on the current magnitude and not on its withdrawal point. It is argued that enhanced nonresistive superconducting anisotropy limits current penetration to less than the London length and results in a flat rectangular resistive region with simultaneous "ab" and "c" current breakdown which moves progressively out from the injection point with increasing current. Measurements in "ab" or "c" configurations are seen to give the same information, involving both ab-plane and c-axis conduction properties.