REEL-TO-REEL TEXTURE ANALYSIS OF HTS COATEDCONDUCTORS USING A MODIFIED GADDS SYSTEM

摘要

High temperature superconducting (HTS) materials need a high degree of texture over kilometer-longrnlengths in order to carry the maximum amount of supercurrent for electric power industryrnapplications. One way to achieve the high degree of texture is with the coated conductorrnarchitecture. The coated conductor is comprised of the HTS layer epitaxially grown on arntextured oxide buffer layer on a metal tape which gives flexibility and strength to the multilayerrnconductor. Traditionally a 360o phi scan is conducted on a small centimeter-wide sample torndetermine the (111) texture of the buffer layer. The pole figure full-width at half-maximumrn(FWHM) is calculated for the (111) peaks to quantify the texture of the buffer layer. This polernfigure FWHM value is a critical quality control parameter, since the current-carrying capabilityrnof the HTS material increases as the FWHM decreases. The texture of the HTS coatedrnconductors was characterized using a Bruker AXS General Area Detector Diffraction Systemrn(GADDS) which was modified to analyze meter-long lengths of conductor. The unique reel-to-reelrnsample holder design, coupled with the parallel beam produced by the cross-coupled G?belrnmirrors in the GADDS system, allows fast and accurate pole figure FWHM determination atrnselected points along meter-long samples. System modifications and texture results for samplesrnup to 10 meters long are described.