Physical and dielectric properties of Bi 4 − xRxSr 3 Ca 3 Cu 2 O 10 glasses ( x = 0 . 5 and R = Ag , Ni )

The reflectivity spectra of semiconducting Bi4Sr3Ca3Cu2O10 glasses were measured over the frequency range between 100 and 4000 cm−1, and were analysed using Kramer-Kronig routines. It is observed that the static and high frequency dielectric constant varies as the bismuth is partially replaced by silver and nickel. The X-ray diffraction and the dc resisitivity measurements shows a semiconducting behaviour for all the samples. The measured values of the activation energy and other physical parameters based on infrared reflectance measurements are consistent with published work on the similar materials, the activation energy W , hopping energy WH and other physical parameters vary with the nickel and silver substitutions. It is shown that the hopping in these materials occurs in non-adiabatic regime, unlike other transition metal oxide glasses. C © 1999 Kluwer Academic Publishers