Micro-Raman spectroscopy as a unique tool for phase characterization of Bi-2212/Ag tapes

In this work, we present reference Raman spectra of Bi-2212/Ag tape as evidence that micro-Raman spectroscopy constitutes a rapid and sensitive evaluation tool for high T_c superconductive cuprate (HTSC) tapes. We performed the characterization for the surface and cross sectional areas of tapes, with spot diameters smaller than 1 μm. The results of this study confirm that local phase characterization is possible for Bi-2212/Ag tape. Our further attempt to carry out a micro-Raman spectroscopy mapping measurement for the Bi-2212 phase yielded meaningful phase and grain alignment distribution data, even though the measurement spacing was rough and the small observation area. With appropriate upgrades for full-scale characterization with fine measurement spacing and a large observation area, we believe that this spectroscopy will be an effective tool to detect and evaluate precise local changes in Bi-2212/Ag tape. The Raman imaging for Bi-2212/Ag may have a substantial potential to distinguish the distribution of the impurity oxide, degree of grain orientation, crystallinity, nonstoichiometry of the main phase, and other relevant characteristics.