Nonlinear physical properties of amorphous Bi4Sr3Ca3CuyOx semiconducting oxides with y between 0 and 5.

Abstract

We report the nonlinear behavior of the CuO-concentration-dependent density (\ensuremath{\rho}), mean molar oxygen volume (${\mathit{V}}_{0}^{\mathrm{*}}$), and electrical conductivities (both ac and dc) of the ${\mathrm{Bi}}_{4}$${\mathrm{Sr}}_{3}$${\mathrm{Ca}}_{3}$${\mathrm{Cu}}_{\mathit{y}}$${\mathrm{O}}_{\mathit{x}}$ (y=0--5) semiconducting oxide glasses. Infrared-spectroscopic data and mean molar oxygen volume (${\mathit{V}}_{0}^{\mathrm{*}}$) in these glasses indicate a change of [${\mathrm{BiO}}_{6}$] octahedral structural unit to pyramidal [${\mathrm{BiO}}_{3}$] structural unit with a change of CuO content in the glasses. However, no direct x-ray structural data of these glasses are found to show evidence of such changes. The nonlinearity is associated with the nonlinear variation of the ratio of [${\mathrm{Cu}}^{+}$]/[Cu(total)] in the glasses depending on CuO concentrations, melting temperatures of the glasses, etc.