Observation of spin-lattice relaxations of dilute Fe3+ in MgO by Mössbauer spectroscopy

We present a method to describe the temperature dependence of emission Mössbauer spectra showing slow spin-lattice relaxations of Fe3 + in MgO single crystals, obtained after implantation of 57Mn at ISOLDE/CERN. The analysis is based on the Blume-Tjon model for the line-shape of relaxing paramagnetic sextets with the spin relaxation rate, ? - 1 as a parameter. The temperature dependent spin relaxation rate of Fe3 + in MgO is found to increase to ~108 s - 1 at 647 K by assuming a relaxation rate of ? - 1 < 106 s - 1 at 77 K. The results are in accordance with those obtained by electron paramagnetic resonance spectroscopy demonstrating the possibility of retrieving spin-lattice relaxation rates of dilute Fe3 + from emission Mössbauer spectroscopy of Mn/Fe-implanted oxides.