Synthesis and magnetic properties of barium–calcium hexaferrite particles prepared by sol–gel and microemulsion techniques

The preparation of W-type hexaferrite particles with the composition BaCa2Fe16O27 by microemulsion and a stearic acid sol–gel method with and without surfactant has been investigated at various sintering temperatures. The structural and magnetic characteristics have been studied by X-ray diffraction (XRD), a vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetric (DSC) and Fourier transform infrared (FTIR) techniques. The effect of sintering temperature on the properties of BaCa2Fe16O27 hexaferrites has been studied. The value of saturation magnetization (Ms) depends on types of surfactant used. The sample prepared in the presence of polyoxyethylene (20) sorbitan monooleat (Tween 80) shows low saturation magnetization (Ms=15.10 emu/g), whereas the other sample prepared in the presence of a surfactant cetyltrimethylammonium bromide (CTAB) exhibits high saturation magnetization (Ms=24.60 emu/g) compared to the normal sample.