Mössbauer studies of Fe2O3 antiferromagnetic small particles

Abstract
Granular films consisting of finely dispersed Fe2O3 grains in an Al2O3 matrix have been studied by means of Mössbauer spectroscopy and magnetization measurements. The temperature dependence of the relaxation time is coherent with the superparamagnetism model only if in the τ0 calculation, the noncompensated moment of the antiferromagnetic particles, is considered. This moment is proportional to (n)1/2, n being the number of magnetic atoms in the particle.