Synthesis and characterization of hexagonal ferrite Co2Sr2Fe12O22 with doped polypyrrole composites

Y-type hexagonal ferrite Co₂Sr₂Fe₁₂O₂₂ was prepared by microemulsion route. A conducting polymer, polypyrrole was chemically synthesized and doped with dodecylbenzenesulphonic acid (PPy·DBSA). FTIR and magnetic properties of Co₂Sr₂Fe₁₂O₂₂ were investigated and compared with composite made by mixing the Co₂Sr₂Fe₁₂O₂₂ with this conducting polymer PPy–DBSA by 1:1 molar ratio. Phase analysis was performed by using X-ray diffraction (XRD). The microstructure was examined by scanning electron microscopy (SEM) showing heterogonous distribution of grains. The field dependent magnetic properties of the prepared samples were investigated at room temperature by using vibrating sample magnetometer (VSM). It has been observed that mixing of polymer in ferrite plays a crucial role in enhancing the coercivity, while saturation magnetization (M_s) and remanance were observed to decrease. Due to fine grain size, the density of grain boundaries increases where the domain wall pinning can take place, hence the coercivity of the composite samples increases. Appreciable improved value of coercivity guaranteed the use of these synthesized materials in the recording media, which is =1896(Oe) in the present samples. The suitable signal-to-noise ratio in the high density recording media can be achieved due to small particles size of this synthesized composite, which is expected in the present ferrite–polymer composite sample.