Effect of Fe deficiency on the crystalline structure and magnetic properties of M-type strontium hexaferrite

In this study, we prepared a single M-type strontium ferrite phase with different iron contents using the traditional ceramic method and studied the effect of iron deficiency on the crystalline structure and magnetic properties of M-type hexaferrite strontium has been studied. With the decrease in iron content, the saturation magnetization of M-type strontium ferrite SrO·nFe2O3 powders (5.49 ≤ n ≤ 5.95) decreases by 5.5% and 4.7% at 300 K and 5 K, respectively. The change in Fe3+ occupancy was determined using X-ray diffraction spectroscopy. The occupancy of Fe3+ in sublattices 2a, 12k and 4f1 decreased with decreasing Fe content, and the decreased amplitude was in the order 2a > 4f1 > 12k. In addition, the (4f1 site) Fe3-O2-Fe5 (12k site) and (4f1 site) Fe3O2 bond length decreased and increased, respectively, with decreasing Fe content. These results are of great significance for improving the magnetism of SrM by regulating iron vacancies in its structure.