The electronic properties of calcium borate glasses containing iron oxide have been investigated. It was found that glasses with an Fe2O3content less than 20 mole were amorphous, while those above 20 mole were devitrified. It was observed that increasing the iron molar content in the amorphous samples caused an increase in their dc conductivity, ac conductivity, dielectric constant, and in the frequency of the dielectric loss peak. Thermoelectric power measurements in the temperature range 400–800 °K indicate that all glasses werentype. The experimental results support the idea of hopping of electrons between the iron ions in the different valence states. An attempt to explain the dc and ac conductions of this system on the basis of a band model and structural changes is presented.
展开▼
