Quantification of pinning center thickness in conventionally processed and powder processed artificial pinning center microstructures

摘要

The quantity, size and distribution of pinning centers are key factors in determining the J/sub c/ of Nb-Ti-based superconductors. In Artificial Pinning Center APC composites large strains must be applied between the assembly of the pinning structure and the final strand, which can result in large changes and variations in pinning center size and shape. In order to correctly interpret the properties of artificial pinning structures, we need an accurate description of their geometry. In this paper we discuss the various techniques available for quantifying near optimum size microstructures and compare the results. We also contrast the distributions found in APC style microstructures with those produced by conventional processing.