Transport mechanism in nonconventional bismuth cuprate glass

Temperature and compositional dependence of the electrical transport properties of the nonconventional binary bismuth cuprate glasses are reported for the first time. It has been observed that the phonon assisted small polaron hopping model in the nonadiabatic regime is consistent with the data only at high temperatures. The variable range hopping model can fit the low temperature data qualitatively. The polaron hopping models proposed by Schnakenberg [Phys. Status Solidi 28, 623 (1968)] and Emin [Phys. Rev. Lett. 32, 303 (1974)] can predict quantitatively the conductivity data in the entire temperature range of measurement for all glass compositions. The physical parameters obtained from the best fits of these models are found reasonable and consistent with the glass compositions. (C) 1996 American Institute of Physics.