Micromechanical Properties of Gd3Ga5O12 Crystals Irradiated with Swift Heavy Ions

This study investigated the optical absorption and mechanical behavior of Gd₃Ga₅O₁₂ (GGG) single crystals exposed to fast 84 Kr ions at fluences ranging from 1013 to 1014 ion/cm². We observed that the optical absorption spectra of GGGs grown using the Czochralski method feature distinct narrow lines in the UV spectrum, attributable to the 4f-4f transitions in Gd³⁺. Clear changes were identified from the 6S 7/2 base state to the ⁶P, ⁶J, and ⁶D states within the Gd³⁺ cation. An unexpected absorption band was also detected at 350 nm, likely resulting from unintentional Ca contamination. After ion exposure, the fundamental absorption edge shifted by approximately 30 nm towards the longer-wavelength section of the spectrum. Our hardness tests indicated a softening effect post-ion exposure, possibly linked to ion-triggered amorphization.