Polaronic Hopping Conduction In Fe203-Pb0-B203 Glasses

DC electrical conductivity measurements have been carried out for xFe203.(100-x)[Pb0.3B203] glasses. Mott's model for the phonon assisted hopping of small polarons is effective to describe the high temperature conductivities. The high temperature activation energy increases linearly with the Fe-Fe distance. At a constant temperature the phonon frequency is proportional to the site separation. The pre-exponential factor is predominant in changing the conductivity. The variable range hopping relations are valid also for the high temperature region. The conduction process is adiabatic in nature.