Influence of microcracks and anisotropic conductivity on critical current and exponent n in silver-sheathed HTS tapes

The influence of filament non-uniformities (microcracks) and anisotropic conductivity on critical current and exponent n of the current-voltage characteristic of HTS/Ag tape conductors was studied numerically by the means of the finite element method. According to the results, non-uniformities reduce the critical current of the conductor, the reduction by a crack being higher in the cases of anisotropic than isotropic conductivity, but their influence on exponent n is negligible. The result suggests that the low n-values of HTS/Ag conductors are due to intrinsic effects such as thermally activated flux creep.