DC CONDUCTIVITY OF SOL-GEL DERIVED GLASSES IN THE SYSTEM FE2O3-SIO2

Glasses in the series x Fe2 O3.(1-x) SiO2 with 0.01 < x < 0.1 have been prepared by sol-gel technique. DC resistivity of these glasses have been investigated over the temperature range 300 to 600K. The temperature variation of resistivity is explained on the basis of a small polaron hopping conduction mechanism, the Fe2+ and Fe3+ ions acting as the hopping sites. The high temperature data have been analysed by both the T-1/4 and T-2/5 law respectively as formulated by Triberis and Friedman. The density of localised states is calculated to be in the range 10(19)-10(20) eV-1 Cm-3.