Mössbauer relaxation spectra of LiNbO3: Fe(III)

Mossbauer spectra of LiNbO3: Fe(III)-monocrystals were measured in zero external magnetic field (5mK to 673K). They all show typical lineshapes due to relaxation effects. Below 77K temperature independent and above 77K a temperature-dependent relaxation is observable. In spectra measured in external magnetic fields relaxation effects occur only above 77K. We present least square fits of spectra measured at 300K and external magnetic fields using symmetry invariant reservoir spectral densities. The applied numerical formalism takes the complete electronuclear manifold of57Fe(III) into account. We discuss the problems concerning the interpretation of zero field spectra.