Berlin 2024 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 10: Diamond and Related Dielectric Materials I

KFM 10.1: Invited Talk

Tuesday, March 19, 2024, 09:30–10:00, E 124

Exploring of the accumulation and thermal annealing of radiation defects in metal oxides via optical absorption, EPR and luminescence methods — •Aleksandr Lushchik — Institute of Physics, University of Tartu, W.Ostwald str. 1, 50411, Tartu, Estonia

High tolerance to intense radiation encourages the use of metal oxides in fission-reactor technologies and allows considering them as promising window materials for the projected fusion facilities. The functionality of optical materials is determined by the creation and accumulation of interstitial-vacancy Frenkel pairs, which are predominantly created via the elastic collisions of fast neutrons/ions with material nuclei.

The radiation damage caused by fast neutrons or ~GeV heavy ions was studied in Al2O3, MgO, MgAl2O4 crystals via optical and EPR methods. The correlations between the EPR and optical characteristics (emission/absorption bands) allowed the tracking of the creation and thermal annealing of F-type defects (an oxygen vacancy with one/two trapped electrons) in MgO, corundum and mineral spinel. The measured annealing kinetics of the F and F+ centers were modelled in terms of diffusion-controlled reactions. A number of novel EPR-active radiation defects was revealed in spinel (set of hole-type V centers) and corundum (a single oxygen interstitial; a double charged F2 dimer). The ability and limitations of the use of cathodoluminescence as a control tool of radiation damage recovery in corundum was considered.

Keywords: radiation defects; optical absorption; Electron paramagnetic resonance; cathodoluminescence; metal oxides