Advances in XRD Characterization of 2G HTS Wire for Low-Temperature Magnet Applications

Industrial 2G HTS wires optimized for low-temperature application are studied using XRD. We aim at understanding the origin of noticeable variation of the lift factor LF = J c (20K, 8T)/ J c (77 K, sf) with the final goal of narrowing down the statistical scatter of the performance in production wires. Two approaches are used - (1) the direct characterization of Y123 defect state through analysis of diffuse scattering effects and (2) quantification of YBCO nanostructure (contents of Y 2 O 3 precipitates, their size, strain state of Y 2 O 3 precipitates and Y123 matrix). Only weak correlations between the parameters extracted from XRD patterns and J c (20K, 8T) have been found. A rather complex strain state of Y123 with out-of-plane tension, anisotropic in-plane compression, and (likely) overall contraction is observed. Further plans are discussed.