Anisotropy field measurement and magnetization reversal in (Co-Ti) substituted hexaferrites

The authors have investigated six industrially produced fine BaFe _12-2xCo_xTi_xO₁₉ powders prepared by the crystallization method. The amount of Co-Ti was determined by thermomagnetic analysis, and the anisotropy field was measured using the transverse susceptibility measurement technique. The calculated ration H_c/H_A was <0.30. This value is much smaller than that predicted by the Stoner-Wofarth theory (0.48) for coherent rotation, suggesting that for Co-Ti-substituted-hexaferrite fine particles, another mechanism for magnetization reversal must be considered. The effect of the specific surface area on the saturation magnetization has also been investigated and shown to agree with results reported in the literature