engleski

Structural and electrical properties of iron phosphate glasses

The relationship between structure and electrical properties for iron phosphate glasses containing different content of alkali and alkaline earth oxides has been studied. The structural changes of these glasses have been investigated by Raman spectroscopy. The Raman spectra show that the iron play an important role in formation of P-O-Fe bonds that strengthens the cross bonding of shorter phosphate chains. The electrical conductivity of these glasses has been measured by thermally stimulated current and impedance spectroscopy. The investigation of cesium iron phosphate glasses has shown that the slowly moving cesium ions are more tightly bound to the non-bridging oxygen ions and make no measurable contribution to the dc conductivity in glasses containing up to 28 mol% Cs2O. The dc conductivity in these cesium-containing glasses is totally electronic, controlled by hopping between iron ions. The electrical conductivity in the mixed alkali, sodium and potassium, iron phosphate glasses is also nearly independent of the different sodium and potassium content. This independence indicates that the mobility of sodium and potassium is almost invariant in the single and mixed alkali iron phosphate glasses. The electrical changes that are appeared in the alumino-phosphate glasses show that the addition of Fe2O3 content have an effect on the dc conductivity. With increasing Fe2O3 content electrical conductivity depends upon distance between iron ions suggesting electronic conduction. The impedance analysis for these glasses shows that the changes in the electrical conduction mechanisms coincide with the changes in the structure.

Glasses; Electrical conductivity; Raman spectroscopy

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