Published online by Cambridge University Press: 25 February 2011
Implantation of iron Into α-Al2O3 at 77 K produces an amorphous state for fluences greater than about 3 × 1016 Fe/cm2. Iron in the as-implanted (amorphous) specimens is distributed among two Fe2+, two Fe4+, and the Fe° states. The conversion electron Mössbauer (CEMS) spectra for a sample containing 7 × 1016 Fe/cm2 show all iron to be converted to Fe3+ after annealing in oxygen for 1 h at 700°C and above. The transmission electron microscopy (TEM) shows the structure to be mostly Y-A120, after the 900°C anneal and all α-Al2O, after the 1100°C anneal.