Superparamagnetism and the Mössbauer spectrum of goethite: a comment on a recent proposal by Coeyet al

The distinctive Mössbauer spectra of goethite cannot be explained on the basis of superparamagnetism. Consideration of superparamagnetic fluctuations in only the transverse components of the sublattice magnetization (`mode superparamagnetism', proposed by Coey et al ), or of possible interactions between superparamagnetic particles, does not alter this conclusion.