Published online by Cambridge University Press: 28 February 2011
LiNbO3 tolerates large amounts of disorder in the form of Li2O- deficiency, oxygen-deficiency, and substitutional impurities. These should all result in the formation of a self-consistent set of lattice defects, and there will thus be interactions between the different types of disorder. It is shown that reduction will result in an increase of the Li2O activity in LiNbO3 when it is kinetically hindered from exchanging Li2O with its surroundings. This is in fact the situation for exposure to reducing atmospheres for several hours near 1000°C. Available data on compositions and defect concentrations at 1050°C indicate that reduction should result in separation of a Li20-rich second phase for oxygen partial pressures below 10−17 about 10 atm. Evidence for such phase separation is described.