The Moessbauer effect in finely ground powders on iron oxide

It is shown that in NMR spectra of fine powders of Fe2O3 and Fe3O4 the line broadening is equal to 50-60%. At the same time, an effective magnetic field on the nuclei of 57Fe reduces by 10-15 kOe. An increase in the intensity of supply of mechanical energy wipes out almost completely the hyperfine magnetic structure of the spectra of α-Fe2O3 and gives rise to a paramagnetic component, just as it does in the spectra of ultrafine particles (approximately 100A). The transformation is considered from the standpoint of the conception on the critical volume and high deficiency of particles obtained