Scanning Raman spectroscopy for inline characterization of 2G-HTS conductors

Abstract

Abstract We report on a feasibility study of using Raman micro-spectroscopy as a characterization method for quality control of REB a 2 C u 3 O 7 − δ (REBCO, rare-earth barium copper oxide) coated conductors (CC). Fragments of long REBCO tape deposited using advanced metal organic chemical vapor deposition with dropouts in critical current (I c) were analyzed implementing Raman spectroscopy in area scan (map) and linear scan modes, in order to evaluate the level of information obtainable with the technique. The areal maps have been found to provide detailed information on the spatial distribution of the sample quality, providing maps of both intensity and wavelength shift characteristic of Raman-active peaks. The maps readily identify defective regions ranging from completely misoriented a-axis domains (REBCO a-axis || sample normal), as well as regions with well-textured c-axis orientation (REBCO c-axis || sample normal) but with significant variation in cation disorder. The results are complemented with linear scans carried out by two-dimensional x-ray diffraction, which do identify the a-axis grain regions but do not detect any apparent anomaly in the cation-disordered region detected by Raman micro-spectroscopy. The results indicate that scanning Raman spectroscopy has the potential to be utilized as a fast, insightful, and reliable characterization, quality, and process control technique for both CC optimization and increase of manufacturing yield.