Abstract
Corundum (α-Al2O3) possesses a number of unique properties, including high tolerance to harsh radiation environment. Material functionality is strongly affected by radiation-induced structural defects, single interstitial-vacancy Frenkel pairs and their aggregates. Three novel paramagnetic two-electron defects with total spin S = 1 have been revealed in fast neutron irradiated α-Al2O3 single crystals by means of the EPR method. Analysis of the EPR characteristics of these defects allows to conclude that the main novel D1 defect (initial concentration after irradiation about 2.8 × 1016 cm−3) is oriented along one of three equivalent b crystal axes, that connect two adjacent anion sites of oxygen triangles on the base corundum plane. The D1 defect is ascribed to the F22+ center (two adjacent single-charged oxygen vacancies), while the D2 and D3 have the same dimer structure with an additional defect in their vicinity. The suggested defect structure is supported by pulse annealing of the EPR signal of relevant defects: defect concentration dependence contains a rising stage at 500–630 K, while complete thermal destruction due to the recombination with complementary oxygen interstitials occurs by 720–750 K. Such behavior qualitatively coincides with earlier studied thermal annealing of the F22+ center optical absorption in neutron-irradiated corundum.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
