Optical reflectivity of superconducting Bi 3.9Pb 0.1Sr 3Ca 3Cu 4O x obtained by glass-ceramic route in 0.6–6.2 eV range

Abstract

The room temperature reflectance spectra in the UV-VIS-NIR region (0.6–6.2 eV) for the superconducting ceramic phase of Bi 3.9Pb 0.1Sr 3Ca 3Cu 4O x, obtained by glass-ceramic route have been studied by Kramers-Kronig (KK) analysis. From these analyses, the real (ε′) and imaginary (ε″) parts of the complex dielectric function, ε = ε′ + iε″, optical conductivity (σ′) and the absorption spectra (α) have been determined. These studies have indicated the presence of plasmon around 1 eV and have also shown that in these oxide systems, BiO and SrO layers have little role to play in the mechanism of superconductivity. The possibility of excitonic absorption in Bi-based high T c superconductors has also been discussed from the knowledge of the absorption spectra.