Studies of (90-x) P_2O_5xB_2O _310Fe_2O_3 glasses by Mossbauer effect and impedance spectroscopy methods

摘要

Glass systems of composition (90-x) P_2O_5 + xB _2O_3 + 10Fe_2O_3 (x = 0 mol.%, 10 mol.%, 20 mol.%, 30 mol.%, 40 mol.%) were prepared using normal melt-quench technique. The Mossbauer Effect has been used intensively to help investigate the structure and bonding of oxide glasses. The M?ssbauer spectra indicate the presence of iron (II) and iron (III) in tetrahedral or octahedral coordination. The dependence of electrical data was analyzed in the frame work of the impedance Cole-Cole plot in a frequency range from 5 Hz to 19.5 MHz at room temperature. Constant-phase elements (CPE) are used in equivalent electrical circuits for the fitting of experimental impedance data. The frequency dependence of the electric conductivity was found to follow a simple power law behavior, in accordance with the relation σ(f) = σ(0) + Af ~s, where s is smaller than 1. The thermal activation energies for the electronic conduction were estimated on the basis of the Arrhenius plots.