Anisotropy field and transverse susceptibility in nanocrystalline hexaferrites

Nanocrystalline strontium and barium hexaferrites were produced by an ionic coordination reaction method. The average particle size obtained using the Rietveld X-ray refinement technique and by scanning electron microscopy was quite uniform and close to 50 nm. Transverse susceptibility measurements yielded both the coercive and the anisotropy magnetic fields. The results were analysed using a theoretical model proposed by Aharoni et al. [Bull. Res. Counc. Isr. A 6 (1957) 215]. This overall procedure seems to be quite useful in determining the distribution of the anisotropy magnetic fields in granular materials.