MOSSBAUER SPECTROMETRY STUDY OF MAGNESIOFERRITE PARTICLES

Fine particles of ferrimagnetic MgFe2O4 were synthesized through a sol -gel supercritical drying procedure, then cold-pressed and heated at 5 00 and 800-degrees-C. These materials were characterized by Mossbauer spectrometry in the temperature range 25-298 K, and in the presence of a small applied magnetic field. The Mossbauer measurements show that heat treatment results in the formation of a small percentage of alpha -Fe2O3, an increase in the mean particle size and hyperfine magnetic f ield, and a decrease in the inversion parameter of the magnesioferrite . An average anisotropy constant equivalent to the bulk magnetocrystal line anisotropy is estimated for particles with diameter D = 14 nm.