Solid state and magnetochemistry of the SrO‐Fe2O3 system IV. Synthesis of SrFe12O19 from coprecipitated precursors

Abstract

By means of 57Fe Mössbauer spectroscopy and powder x‐ray diffraction techniques, it has been determined that the formation of SrFe12O19 from coprecipitated ferric hydroxide and strontium laurate follows a reaction mechanism different from that when SrCO3 and Fe2O3 are used as starting materials. Upon heating at 300 C in vacuum, strontium laurate decomposes and further heating to 550 C leads to the formation of γ‐Fe2O3 from the ferric hydroxide and solid solution of SrO in γ‐Fe2O3. This solid solution phase behaves as an intermediate and undergoes further reaction with γ‐Fe2O3 to give SrFe12O19. No paramagnetic Sr‐Fe oxide intermediate is formed. The low temperature of the reactions and the absence of paramagnetic intermediates offer new possibilities for controlling the textures and magnetic properties SrFe12O19 ceramic bodies.