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 fast heavy 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 dc (5.00 -/+ 0.15) nm, with a surrounding damaged region of dd (10.00 -/+ 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 under at 9 K. In addition, dimers YAl - F+ and/or YAl - F can be formed on the basis of antisite defects with F-like centers due to melting and recrystallization of the material during trace formation under Xe ion irradiation conditions.