Distinctive features of diffusion-controlled radiation defect recombination in stoichiometric magnesium aluminate spinel single crystals and transparent polycrystalline ceramics

A Lushchik; E Feldbach; E A Kotomin; I Kudryavtseva; V N Kuzovkov; A I Popov; V Seeman; E Shablonin

doi:10.1038/s41598-020-64778-8

Distinctive features of diffusion-controlled radiation defect recombination in stoichiometric magnesium aluminate spinel single crystals and transparent polycrystalline ceramics

Sci Rep. 2020 May 8;10(1):7810. doi: 10.1038/s41598-020-64778-8.

Authors

A Lushchik¹, E Feldbach¹, E A Kotomin², I Kudryavtseva¹, V N Kuzovkov², A I Popov³, V Seeman¹, E Shablonin^{1

2}

Affiliations

¹ Institute of Physics, University of Tartu, W. Ostwald Str. 1, 50411, Tartu, Estonia.
² Institute of Solid State Physics, University of Latvia, Kengaraga 8, Riga, LV-1063, Latvia.
³ Institute of Solid State Physics, University of Latvia, Kengaraga 8, Riga, LV-1063, Latvia. popov@latnet.lv.

Abstract

MgAl₂O₄ spinel is important optical material for harsh radiation environment and other important applications. The kinetics of thermal annealing of the basic electron (F, F⁺) and hole (V) centers in stoichiometric MgAl₂O₄ spinel irradiated by fast neutrons and protons is analyzed in terms of diffusion-controlled bimolecular reactions. Properties of MgAl₂O₄ single crystals and optical polycrystalline ceramics are compared. It is demonstrated that both transparent ceramics and single crystals, as well as different types of irradiation show qualitatively similar kinetics, but the effective migration energy E_a and pre-exponent D₀ are strongly correlated. Such correlation is discussed in terms of the so-called Meyer-Neldel rule known in chemical kinetics of condensed matter. The results for the irradiated spinel are compared with those for sapphire, MgO and other radiation-resistant materials.