Intra-and inter-grain currents in coated conductors with arbitrary grain boundary properties from magnetic measurements

摘要

A generalized methodology is described for determining both the intragranular and through-grain-boundary critical current densities in practical coated conductors from contact-free magnetic hysteresis measurements. The model incorporates the vector nature of current density J within the superconducting grains and current conservation with respect to the grain boundaries. Using physically observed values for the grain aspect ratio as input, the analysis yields the low-field intragranular critical current density JcG from a single field-dependent measurement of the global J c and provides a consistent description that spans the entire range from the weak-link to the single-grain limit. Results are given for exsitu processed RBCO coatings on RABiTS.