IRON IMPLANTATION IN GADOLINIUM GALLIUM GARNET STUDIED BY CONVERSION-ELECTRON MOSSBAUER-SPECTROSCOPY

Gadolinium gallium garnet single crystals were implanted with doses of Fe-57 ions in the range 8 x 10(15)-6 x 10(16) atoms cm(-2). Depending on the dose, iron with Fe2+ or Fe3+ charge states was found to have f ormed after the implantation. After a subsequent annealing in air, the iron oxidized to Fe3+. The Mossbauer and channelling measurements sho wed lattice recrystallization taking place at 600 degrees C. After rec rystallization, the iron was found to have substituted for gallium ion s both at the octahedral and at the tetrahedral positions. The relativ e concentration of the two types of iron at the two sites shifted towa rds the equilibrium distribution upon high-temperature annealing.