Raman spectroscopic analysis for grain boundary of Superconducting polycrystalline SmFeAsO$_{\mathrm{1-x}}$F$_{\mathrm{x}}$

The observation of grain boundary structures is essential technique to fabricate high-T$_{\mathrm{c}}$ superconducting wires. Spatial crystal distribution analysis for grain boundary of superconducting polycrystalline SmFeAsO$_{\mathrm{1-x}}$F$_{\mathrm{x}}$ is demonstrated by Raman Spectroscopy. Polycrystalline SmFeAsO$_{\mathrm{1-x}}$F$_{\mathrm{x}}$ samples were synthesized using two-step solid state reaction described elsewhere [New J. Phys.\textbf{12}, 033005 (2010)]. Samples' surface and their structures were checked by microscopic optical measurement and electron beam backscattering diffraction (EBSD) analysis. The Raman spectroscopy was performed at the range from 150 cm$^{-1}$ to 500 cm$^{-1}$. F contents (x) were 0, 0.019, 0.037, 0.045, 0.069, 0.075. Although our several spectra are similar to which had been reported [Hadjiev, et al, Phys. Rev. B. \textbf{77}, 220505 (2008)], our results indicate that grain boundary structures are mixtures of small single crystalline SmFeAsO$_{\mathrm{1-x}}$F$_{\mathrm{x}}$ and amorphous-FeAs. Details of the Raman spectra will be presented at the conference.