Effects of La-Mn co-substitution on the structure and magnetic properties of M-type strontium hexaferrite

Research into enhancing the magnetic properties of permanent ferrite using ion substitution techniques has continued, particularly concerning replacing commercially available La-Co co-substitution ferrite with larger magnetic anisotropy and lower prices. Mn ions with larger magnetic moments have become one of the options. In this work, Sr1-xLaxFe11.6-xMnxO19 (0 ≤ x ≤ 0.5) with equal substitution of La-Mn was synthesized by the conventional ceramic route. X-ray diffraction analyses indicated that the upper limit of La-Mn concentration was 0.4. The lattice constant a increases and c decreases with increasing La-Mn concentrations. With the increase of La-Mn concentrations, Ms reaches the highest value of 80.52 emu/g (x = 0.2) at 300 K. As evidenced by Raman spectroscopy, the substitution sites of Mn ions in the ferrite lattice altered with the substitution concentration, and the substitution tendency was 4f2 > 12 k + 2a > 4f1. In addition, La-Mn substitution affects the inherent magnetic properties such as HA and Tc of the samples, which has a reference for further improvement of permanent ferrites.