Optimization of Magnetic and Structural Properties of Sr Ferrite Prepared by Low-Temperature Combustion

Fine strontium hexaferrite particles were prepared by the low temperature auto-combustion method. Aqueous solution of the corresponding metal salts and a combustible co-reactant compound - glycine were used as initial precursor. The resulting powders were calcined at various temperatures from 750°C up to 1100°C. The microstructure and magnetic properties were investigated by the Mössbauer spectroscopy, thermomagnetic analysis, scanning electron microscopy, and vibrating magnetometer. The particles of sizes less than 1 μm have monophasic hexagonal structure. Coercivity $H_c$≈400 kA/m, specific saturation polarization $J_{s-m} ≈ 72×10^{-6} Tm^3 kg^{-1}$ and remanence polarization $J_{s-r} ≈ 43×10^{-6} T m^3 kg^{-1}$ were achieved for the Sr ferrite annealed at 850°C for 6 h.