H. Farouk et al., ROLE OF IRON ADDITION ON STRUCTURE AND ELECTRICAL AND MAGNETIC-PROPERTIES OF LITHIUM LEAD BORATE GLASSES, Materials science & engineering. B, Solid-state materials for advanced technology, 38(3), 1996, pp. 217-221
The effect of iron oxide addition on the structure and electrical and
magnetic properties of lithium lead berate glasses was studied using I
R transmission spectra: optical absorption techniques, electrical cond
uctivity, magnetic susceptibility measurements and differential therma
l analysis (DTA). IR transmission spectra showed that the addition of
up to 3 mol.% iron oxide to the samples introduced as modifiers at the
expense of Pb ions. When the amount of iron oxide is increased to mor
e than 3 mol.%, the iron enters the glass structure as network former
with an FeO4 structure. The optical absorption properties of glass sam
ples containing different amounts of iron oxide indicated that the oxi
dation state and the coordination of the doping ions are octahedral. A
t high contents of iron oxide, some of the iron ions exist in a tetrah
edral form. The electrical conductivities as a function of temperature
for glass samples containing different amounts of iron oxide up to 10
mol.% Fe2O3 have similar behaviours, from which we deduced the activa
tion energy for each sample. The investigation of the magnetic suscept
ibility as a function of Fe2O3 concentration concluded that, for high
amounts of iron ions, the iron ions exist in an octahedral coordinatio
n rather then in a tetrahedral coordination. DTA showed that the sampl
es containing up to 5 mol.% iron oxide are characterized by one crysta
llization temperature, while samples containing 10 mol.% iron oxide ha
ve two crystallization temperatures.