Electron transport studies in single transition metal ions doped borophosphate glasses

Abstract

Three series of boro-phosphate glasses doped with single transition metal ions, Cuo, Fe2O3 and CoO have been prepared by melt quenching method and investigated for room temperature density and dc electrical conductivity in the temperature range from 325 to 600K. The density increased with increasing transition metal ions concentration in all the three series. The measured conductivities were in the order of 10-7, 10-6 and 10-3 to 10-6 Ω-1m-1 for CoO, CuO and Fe2O3 doped glasses respectively. At all temperatures of interest, the conductivity of Fe2O3 doped glasses was higher than that measured in the other two series of glasses. The conductivity increased with increasing contents of CuO and Fe2O3 in their respective series of glasses. Whereas the conductivity decreased with increasing CoO content in CoO doped glasses. In general, conductivity increased with increasing temperature in all the series and that has been analyzed in view of Mott's small polaron hopping (SPH) model and thereby high temperature activation energies have been determined. Various physical and polaron hopping related parameters such as molar volume, polaron hopping distance, radius, band width etc., have been determined and discussed. It is for the first time that the borophasphate glasses in the present compositions are studied for electron transport properties and subjected to thorough analysis.