1 Department of Physics and Astronomy, Science and Technology, Aarhus University2 University of the Witwatersrand, Johannesburg3 University of Iceland, Reykjavik4 Laboratorio MDM IMM-CNR, MB5 University of Witwatersrand6 University of KwaZulu-Natal, Durban7 EP Division, CERN, Geneve8 University of Iceland9 University of Leuven, Leuven10 Helmholz Forschungszentrum, Berlin11 Department of Physics and Astronomy, Science and Technology, Aarhus University
We have applied implantation of radioactive 57Mn + (T1/2 = 1.5 min) at the ISOLDE facility at CERN with 50–60 keV energy to fluences <1012 /cm2 to study the emission Mössbauer spectra from the 14.4 keV transition of the 57Fe daughter atoms. For fluences ≥5 × 1011 57Mn/cm2, the spectra are dominated by the Fe3 + state exhibiting a slow paramagnetic relaxation. We show that the Fe3 + state in ZnO saturated by <1012 57Mn/cm2 implantations is unstable. The crystals can be reset by annealing at T > 760 K or storage at room temperature for 12 months, after which they show dominantly the Fe2 + state for <2 × 1010 57Mn/cm2 implantations. These findings are discussed in terms of diffusion and/or annihilation of implantation-induced defects.
Hyperfine Interactions, 2013, Vol 221, Issue 1-3, p. 45-51