Radiation-induced disordering in magnesium aluminate spinel subjected to ionizing radiation

An analytical electron microscope study was carried out on single crystal specimens of magnesium aluminate spinel irradiated with 200 MeV Xe14+ ions up to 5.0 x 1015 and 2.0 x 1016 ions/m2 at ambient temperature. Bright-field images showed structurally disordered columns of about 4-5 nm in diameter along ion tracks. Tiny pits were observed on the incident surface of the columns. Quantitative HARECXS analysis of atomic configurations revealed that disordering proceeds in more extended regions over 10 nm in diameter. The configurations of Al3+ ions are more disordered than that of Mg2+ ions. The disordered areas are appeared to overlap each other in the specimen irradiated with 2.0 x 1016 ions/m2