Measured displacement energies of oxygen ions in titanates and zirconates

Optical emission spectra in the 300–700 nm range were collected from four perovskite-structured materials (CaTiO3, SrTiO3, BaTiO3 and CaZrO3), a pyrochlore-structured material (La2Zr2O7) and zirconolite (CaZrTi2O7), using either a Febetron 706 variable energy pulsed-electron-beam generator (pulse duration 3 ns) or a Vickers pulsed-electron LINAC (pulse duration 0.5 μs). The long-lived emissions (up to microseconds after the electron pulse) consist of broad (halfwidths ∼100 nm) bands centred around ∼400 nm. For the CaZrO3, La2Zr2O7 and CaZrTi2O7 samples, the emission intensity per unit dose was also measured as a function of electron beam energy over the range 0.2–0.6 MeV. The data for all three samples suggest a single stage dependence on electron beam energy. CaZrO3, La2Zr2O7, and CaZrTi2O7 have emission thresholds of 0.28 ± 0.03, 0.27 ± 0.03, and 0.26 ± 0.03 MeV respectively, which give oxygen displacement values of 49 ± 5, 47 ± 5, and 45 ± 5 eV respectively. Data collected in this study are discussed in the context of previously measured and calculated oxygen displacement values.