Oxide glasses defects

Bogomolova, L. D., Stefanovsky, S. V., Teplyakov, Y. G. Dmitriev, S. A. 1997. Formation of paramagnetic defects in oxide glasses during the bompardment of their surface with charged particles. Materials Research Society Symposium Proceedings, 465, 657-664. 

Shkrob lA, Tadjikov BM, Trifunac AD. (2000) Magnetic resonance studies on radiation-induced point defects in mixed oxide glasses. 1. Spin centers in BjOj and alkali borate glasses. / Non-Cryst Solids 262 6-34. 

The arrangement of the atoms or ions in the material also needs to be considered. Crystalline ceramics have a very regular atomic arrangement whereas in noncrystalline or amorphous ceramics (e.g., oxide glasses) there is no long-range order, although locally we may identify similar polyhedra. Such materials often behave differently relative to their crystalline counterparts. Not only perfect lattices and ideal structures have to be considered but also the presence of structural defects that are unavoidable in all materials, even the amorphous ones. Examples of such defects include impurity atoms and dislocations. 

Kawazoe H, Effects of modes of glass formation on the structure of intrinsic or photoinduced defects centered on III, IV, or V cations in oxide glasses , J. Non-cryst. Solids, 1985, 71, 213-34. 

The metal has very little commercial use. In elemental form it is a laser source, a portable x-ray source, and as a dopant in garnets. When added to stainless steel, it improves grain refinement, strength, and other properties. Some other applications, particularly in oxides mixed with other rare earths, are as carbon rods for industrial hghting, in titanate insulated capacitors, and as additives to glass. The radioactive isotope ytterbium-169 is used in portable devices to examine defects in thin steel and aluminum. The metal and its compounds are used in fundamental research. 

The common feature of the internal reactions discussed so far is the participation of electronic defects. In other words, we have been dealing with either oxidation or reduction. We now show that reactions of the type A+B = AB can take place in a solvent crystal matrix as, for example, the formation of double oxides (CaO +Ti02 = CaTi03) in which atomic (ionic) but no electronic point defects are involved. Although many different solvent crystal matrices can be thought of (e.g., metals, semiconductors, glasses, and even viscous melts and surfaces), we will deal here mainly with ionic crystal matrices in order to illustrate the basic features of this type of solid state reaction. 

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