Краткое описание

Structural changes in samples of synthesized polycrystalline Sc₃TaO₇ compound of monoclinic modification during thermal exposure in vacuum in the temperature range 25−1800°C, followed by irradiation of samples by xenon ions with energies of 140 and 300 keV, have been studied by X-ray methods. The monoclinic modification was stable during thermal vacuum heating from 25 to 1700°C. The parameters of the lattice of monoclinic modification were measured, the thermal expansion coefficients and their energies were determined in the indicated temperature range. The thermal expansion of the monoclinic cell exhibits a noticeable anisotropy. A phase transformation occurs in vacuum at 1800°C, which leads to monoclinic modification transformation to a tetragonal phase accompanied by the formation of a change in the chemical composition of the compound and by the appearance of defects in the lattice, anion vacancies, and color centers. After irradiation of such samples with ions of xenon with different energies, macro- and micro-tensions appear in the structure that substantially depend on the energy of irradiation over the depth of a sample. The presence of defects in the structure of a compound and their strengthening leads to an anomalous increase in the relative integral intensity of X rays reflected from the surfaces of the cell over the depth of the sample. Mathematical models of the formation of defects in the structure of a compound on thermal and ionic irradiation have been developed and their relationship is shown.