Influence of stoichiometry on the magnetic disaccommodation in M-type Sr hexaferrites

Abstract The relaxation of the initial permeability has been measured in polycrystalline Sr hexaferrites with the initial composition SrO·nFe2O3 (n=5.7, 6), prepared by means of standard ceramic techniques in air as well as CO2 sintering atmospheres. The isochronal disaccommodation spectra show the presence of different relaxation processes, depending on both the sintering atmosphere and especially the initial composition, and associated to ionic reorientations of ferrous cations and lattice vacancies in the different metallic sites within the spinel (S) and hexagonal (R) blocks of the close packed lattice.