EFFECTS OF XE ION IRRADIATION AND SUBSEQUENT ANNEALING ON THE PROPERTIES OF MAGNESIUM-ALUMINATE SPINEL

Single crystals of magnesium-aluminate spinel MgAl2O4 were irradiated with 340 keV Xe2 ions at minus173 C (approximately 100 K). A fluence of 1 x 1020 Xe/m2 created an amorphous layer at the surface of the samples. The samples were annealed for 1 h at different temperatures ranging from 130 C to 880 C. Recrystallization took place in the temperature interval between 610 C and 855 C. Transmission electron microscopy (TEM) images show two distinct layers near the surface: (1) a polycrystalline layer with columnar grain structure; and (2) a buried damaged layer epitaxial with the substrate. After annealing at 1100 C for 52 days, the profile of implanted Xe ions did not change, which means that Xe ions are not mobile in the spinel structure up to 1100 C. The thickness of the buried damaged layer decreased significantly in the 1100 C annealed sample comparing to the sample annealed for 1 h at 855 C