Benefits of current percolation in superconducting coated conductors

TL;DR

This study compares the critical current behavior of different superconducting coated conductors under magnetic fields, revealing how doping and fabrication methods influence current flow and anisotropy.

Contribution

It provides new insights into how doping and fabrication techniques affect percolation and critical current anisotropy in superconducting tapes.

Findings

Undoped MOD/RABiTS conductors show less anisotropy than PLD/IBAD.

Ca doping improves uniformity of critical current.

Doping influences percolation pathways and current flow stability.

Abstract

The critical currents of MOD/RABiTS and PLD/IBAD coated conductors have been measured as a function of magnetic field orientation and compared to films grown on single crystal substrates. By varying the orientation of magnetic field applied in the plane of the film, we are able to determine the extent to which current flow in each type of conductor is percolative. Standard MOD/RABiTS conductors have also been compared to samples whose grain boundaries have been doped by diffusing Ca from an overlayer. We find that undoped MOD/RABiTS tapes have a less anisotropic in-plane field dependence than PLD/IBAD tapes and that the uniformity of critical current as a function of in-plane field angle is greater for MOD/RABiTS samples doped with Ca.