Emission Mössbauer spectroscopy study of fluence dependence of paramagnetic relaxation in Mn/Fe implanted ZnO

Emission Mössbauer Spectroscopy following the implantation of radioactive precursor isotope 57 Mn + ( T 1/2 = 1.5 min) into ZnO single crystals at ISOLDE/CERN shows that a large fraction of 57 Fe atoms produced in the 57 Mn beta decay is created as paramagnetic Fe 3+ with relatively long spin-lattice relaxation times. Here we report on ZnO pre-implanted with 56 Fe to fluences of 2×10 13 , 5×10 13 and 8 × 10 13 ions/cm 2 in order to investigate the dependence of the paramagnetic relaxation rate of Fe 3+ on fluence. The spectra are dominated by magnetic features displaying paramagnetic relaxation effects. The extracted spin-lattice relaxation rates show a slight increase with increasing ion fluence at corresponding temperatures and the area fraction of Fe 3+ at room temperature reaches a maximum contribution of 80(3)% in the studied fluence range.