Synthesis and characterization of nano-crystalline strontium hexaferrite using the co-precipitation and microemulsion methods with nitrate precursors

Abstract Nano-crystalline strontium hexaferrite (SrFe 12 O 19 ) powder was synthesized using the classical co-precipitation and microemulsion methods. The precursors were obtained by precipitating Sr 2+ and Fe 2+ ions using tetramethylammonium hydroxide and calcinating at different temperatures ranging from 400 °C to 1000 °C in air. The influence of the Sr 2+ /Fe 3+ mol ratio and the calcination temperature on the product formation and magnetic properties were studied. The formation of nanosized particles of SrFe 12 O 19 with a relatively high saturation magnetization M s = 64 Am 2 /kg, remanent magnetization of M r = 39 Am 2 /kg and a coercitivity of H c = 5.5 kOe was achieved at a Sr 2+ /Fe 3+ mol ratio of 1:8 calcined at 900 °C. The formation of the SrFe 12 O 19 was inspected using XRD analysis, thermogravimetric analysis (TGA), differential thermal analysis (DTA), TEM, and magnetic measurements.