Synthesis of coprecipitated strontium hexaferrite nanoparticles in the presence of polyvinyl alcohol

Strontium hexaferrite (SrFe₁₂O₁₉) nanoparticles were synthesized by the chemical coprecipitation method and using polyvinyl alcohol (PVA) as a protective agent. The synthesized samples were characterized by differential thermal analysis, X-ray diffraction, scanning and transmission electron microscopy, particle size analyzer, sedimentation test and vibrating sample magnetometer. In the presence of PVA, the single-phase SrFe₁₂O₁₉ nanoparticles were obtained at low temperature of 650 °C. The average particle size of SrFe₁₂O₁₉ precursor was 15 nm, which increased to 61 nm after calcination at 650 °C. The magnetic measurements indicated that PVA decreased coercivity from 4711 to 3216 Oe with particle size reduction. The results showed that PVA as a protective agent could be effective in decreasing the particle size, calcination temperature and coercivity of SrFe₁₂O₁₉ nanoparticles.