Optical, channeling and MÖssbauer studies of high dose iron implanted ionic crystals

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Abstract
The association of optical absorption, channeling and conversion electron Mössbauer techniques has been applied to the study of high dose iron implantation (6 × 1016 57Fe+.cm−2) phenomena in MgO single crystals. After implantation defects in the oxygen sublattice (F-type centers) and in the magnesium sublattice (V−-centers) have been observed as well as superparamagnetic iron precipitates (size ∽20 Å) and Fe2+ ions. After thermal annealing for one hour at 700°C in argon atmosphere, all the iron species are converted mainly into Fe3+ ions contributing to the stabilization of F-type centers. A part of them is magnetically ordered even at room temperature, the other remaining paramagnetic down to 4.2 K. This could correspond to a bipartition in the Fe2O3 particle sizes: 50 to 80 Å and 16 57Fe+ ions. cm−2 are also reported