Magnetic properties of Sn–Mg substituted strontium hexaferrite nanoparticles synthesized via coprecipitation method

Nanoparticles of Sn–Mg substituted strontium hexaferrite with the composition of SrFe12−x(Sn0.5 Mg0.5)xO19 (x = 0.0–1.0) were synthesized by chemical coprecipitation method. Deionized water/ethanol (50/50) was used as the solvent. The single phase strontium hexaferrites were obtained at pH 13 and Fe3+/Sr2+ molar ratio of 9 after calcination at 800 °C. The mean particle size of samples was decreased from 82 to 56 nm with increasing the Sn–Mg content from x = 0.0 to x = 0.8. The effect of Sn–Mg substitution on magnetic properties of hexaferrites was studied using vibrating-sample magnetometer. It was found that increasing the Sn–Mg from x = 0.0 to x = 0.8 reduced the coercivity from 4728.9 to 1455.5 Oe and increased the saturation magnetization from 51.34 to 65.49 emu/g. A vector network analyzer was used to investigate the microwave absorption properties. According to microwave measurements, doped strontium hexaferrite composites had much more effective electromagnetic absorption properties than undoped strontium hexaferrite composite.

► Decreasing mean particle size from 82 to 56 nm with increasing the Sn–Mg proportion from x = 0.0 to x = 0.8. ► Reducing the coercivity from 4728.9 to 1455.5 Oe and increasing the saturation magnetization from 51.34 to 65.49 emu/g with increasing the Sn–Mg from x = 0.0 to x = 0.8. ► The higher effective electromagnetic absorption properties for strontium hexaferrite–acrylic resin composites which contained doped hexaferrite with x = 0.8.