Structure and Magnetic Properties of Co-Substituted Strontium Hexaferrite

Abstract

The strontium hexaferrite (SrFe12O19) and Co-substituted strontium hexaferrite (SrCoFe11O19) were prepared by ceramic method. The milled mixture of Fe2O3, SrCO3 and CoO powders were calcined at 1100°C and pellets sintered at 1300°C in air. The crystal structure, morphology and magnetic properties of samples have been investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM), respectively. The crystal structure of SrFe12O19 was hexaferrite with the crystallite size and the lattice constants a and c of 59.6 nm, 5.8 Å, and 23.0 Å, respectively. Also, the crystal structure of SrCoFe11O19 was hexaferrite with the crystallite size and the lattice constants a and c of 63.7 nm, 5.9 Å and 23.0 Å, respectively. The morphology of obtained samples changed from hexagonal rods to discs shape and grain sizes increased with the increase of doped Co in SrFe12O19. SrFe12O19 with the coercive force (Hc) of 2,133 Oe was classified as hard ferrite magnetic. While, Co-substituted strontium hexaferrite (SrCoFe11O19) was soft ferrite magnetic with coercive force of 64 Oe. Results indicated that magnetic properties of samples such as hard ferrite magnetic and soft ferrite magnetic showed great dependence on the cobalt additive in strontium.