부산대학교 도서관

The phase generation in the Lu(Gd)–Ti–O systems is studied at 20–1000°С using a co-precipitation method. During a thermal treatment of co-precipitation products after a sublimation dehydration, for a composition with the Lu : Ti cation ratio of 1 : 1, an Lu2Ti2O7phase with a fluorite structure forms at 650°С. At 730–750°C the phase undergoes a fluorite ⇔ pyrochlore transition. Above 750°C its structure is that of disordered pyrochlore, in which antistructural defects occur in Lu and Ti positions (up to 18%). Above 900°C the structure of pyrochlore becomes ordered, and the number of defects in Lu and Ti positions decreases, which affects the temperature dependence of permittivity of Lu2Ti2O7. In Gd–Ti–O system, Gd2Ti2O7is crystallized, which has a pyrochlore structure only at 740–900°С. Electroconductivity and permittivity of Lu2Ti2O7and Gd2Ti2O7are measured.