Microstructure and Dielectric Properties of BaFe12O19 Hexaferrite Nanoparticles: Effect of Cobalt Addition and Calcination Temperature

M-type Barium Hexaferrite (BaFe12O19) is a promising compound for technological applications because of its high permeability, high saturation magnetization and excellent dielectric properties. In this study, the microstructure and dielectric properties of CoxBaFe12O19 Hexaferrite were investigated. The co-precipitation method was employed to prepare CoxBaFe12O19 nanoparticles, with x = 0, 0.04, 0.06 and 0.1 wt. %, at two different calcination temperatures (900 degrees C and 950 degrees C). The microstructure of the samples was examined through X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The hexagonal structure of the prepared samples was confirmed from XRD results. TEM images reveal the formation of agglomerated nanoparticles with different size distribution. The dielectric properties of the samples were studied through HIOKI 3532-50 LCR-Hi TESTER as a function of frequency (100 kHz-3MHz) and temperature (25 degrees C-500 degrees C). The effects of Co addition, frequency and temperature on the dielectric constants (epsilon' and epsilon ''), loss tangent (tan delta) and ac conductivity (sigma(ac)) have been explained on the basis of hopping of electrons between Fe2+ and Fe3+ ions.