D. Narducci et al., ELECTRONIC CONDUCTIVITY IN COPPER-BASED AND IRON-BASED PHOSPHATE-GLASSES EXHIBITING CLUSTERING AND SPINODAL DECOMPOSITION, Journal of materials chemistry, 3(11), 1993, pp. 1179-1185
The results of an extended study of structural, chemical, spectroscopi
c and electrical properties of oxide glasses are reported. The aim of
this investigation was to explore the effect of progressive clustering
and incipient spinodal segregation on the electrical properties of gl
assy oxides. Zinc phosphate glasses containing variable amounts of cop
per or iron oxides were prepared by quenching and were characterized c
hemically, electrically and structurally. The transition-metal-ion sym
metry in the glass was confirmed to be lower than spherical, with the
hopping-centre electronic levels splitting accordingly. In Cu glasses
clustering is found to occur and to affect the hopping regime. Further
more, the matrix structure is seen to affect the glass properties. In
iron-based materials, microscopic segregation is additionally observed
. Electrical data fulfil the standard hopping-model predictions at ver
y low concentrations only. For total iron contents >5 mol%, spinodal d
ecomposition of supersaturated glassy solutions must be invoked.