THERMALLY STIMULATED LUMINESCENCE FROM COMMONLY OCCURRING IMPURITY PHASES IN HIGH-TEMPERATURE SUPERCONDUCTORS

The insulating materials Y2O3, Y2BaCuO5, BaCO3, Ba3CuO4, and BaCuO2, which frequently occur as secondary phases in high temperature superconductors (HTS), have been investigated using thermally stimulated luminescence (TSL). When irradiated with X- or γ-rays at room temperature and subsequently heated to 400°C they produce TSL whose glow-peak maxima occur between 115 and 280°C. Analyses of the TSL glow curves reveal that the trapped charges require energies from 0.7 to 1.2 eV for their release from metastable states following mixed-order kinetics ranging from 1.3 to 3 with frequency factors varying from 107 to 1014 s-1. TSL in these nominally pure, single-phase insulating materials are attributed to impurities and radiation-induced ionic radicals. © 1990.