Mossbauer spectra of ferrihydride: superferromagnetic interactions and anisotropy local energy

Abstract
The Mossbauer spectra of a sample of synthetic ferrihydrite have been investigated in the 26-220 K temperature range in order to identify the mechanism giving rise to the relaxation times. The results show that the temperature dependence of the relaxation times is in accordance with the Vogel-Fulcher law. This indicates that the magnetic interaction between the crystallites is significant. From the temperature dependence of the mean magnetic field under TB the authors also argue for a strong correlation between the spatial orientations of neighbouring clusters.