Transport properties of semiconducting Fe2O3-PbO-B2O3glasses

Abstract

Density, DC conductivity and ¹¹B wide-line NMR investigations have been carried out for xFe₂O₃-(50-x)PbO-50B₂O₃ glasses (02O₃. The DC conductivity and the activation energy for conduction change markedly with Fe₂O₃ content. The high-temperature conductivities can be described by Mott's model for the phonon-assisted hopping of small polarons. The polaron hopping is shown to be non-adiabatic. The low-temperature conductivities are characterized by the variable-range hopping mechanism. For Fe₂O₃ contents greater than 15 mol%, glass-crystal composites are formed, changing greatly the electrical properties, and other conduction mechanism is to be assumed.