Structural and optical properties of Y3Al5O12 single crystals irradiated by swift heavy Xe ions.

The multifaceted radiation effects occurring in advanced optical material - the crystals of yttrium aluminum garnet Y3Al5O12, irradiated by swift heavy 230 MeV Xe ions to fluences of 6 × 1010-1013 ions/cm2 have been investigated using various research techniques, including optical absorption, Raman spectroscopy, photoluminescence under excitation by the synchrotron radiation, nanohardness measurements, and high-resolution transmission electron microscopy. The near-surface layer at high fluence becomes amorphous, and material softening indicates destruction of cation-anion bonds due to tracks overlapping. Transmission electron microscopy analysis confirmed the presence of continuous tracks in irradiated Y3Al5O12 crystals at energy losses above 10 keV/nm, whereas lower-energy tracks appear as chains of smaller defects. The core track diameter is dc [Formula: see text](5.00 [Formula: see text] 0.15) nm, with a surrounding damaged region of dd[Formula: see text] (10.00 [Formula: see text] 0.15) nm. An increase in the concentration of oxygen vacancies (F and F+ centers) and YAl antisite defects with increasing irradiation fluence is confirmed through photoluminescence spectra of initial and irradiated crystals at 9 K. In addition, YAl-F⁺ and/or YAl-F dimers may form based on antisite defects associated with F-like centers, as a result of melting and crystalization processes occurring during track formation under Xe ion irradiation.