Effect of heat treatment on the phase composition, structure and magnetic properties of M-type barium hexaferrite

Effect of the heat treatment of carbonate-hydroxide precipitates on the phase composition, structure and magnetic properties of M-type barium hexaferrite has been investigated using the Mőssbauer spectroscopy, X-ray phase analysis and magnetic measurements. The distribution of Fe³⁺ ions over structural sites of barium hexaferrite with different degree of ferritizations has been defined. The conditions of single-domain behavior of barium hexaferrite nanoparticles in the magnetic field have been discussed. Obtained results explain the formation of magnetic structure during the synthesis of barium hexaferrite. This information could further be used for optimizing conditions for synthesis of nanosized barium hexaferrite with high-level properties. - Highlights: • In the T=973–1273 K range, BaFe₁₂O₁₉ (BHF) phase are formed from precipitates. • Fe³⁺ ions prefer to occupy 12k,2a,2b (at 1073 K) and 4f₁,4f₂ (at 1273 K) sites. • The most favorable magnetic structure for high M_s forms at T=1073 K. • The presence of 5–10% of α-Fe₂O₃ phase can improve magnetic properties of BHF