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

Abstract

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 Co_xBaFe₁₂O₁₉
Hexaferrite were investigated. The co-precipitation method was employed to prepare Co_xBaFe₁₂O₁₉ nanoparticles, with x = 0, 0.04, 0.06 and 0.1 wt. %, at two different calcination temperatures (900^oC and 950^oC). 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^°C–500^°C). The effects of Co addition, frequency and temperature on the dielectric constants (ɛʹ and ɛ"), loss tangent  (tan δ) and ac conductivity (σ_ac) have been explained on the basis of hopping of electrons between Fe²⁺ and Fe³⁺ ions.

Keywords: BaFe₁₂O₁₉ Hexaferrite, Co-precipitation method, XRD, Dielectric properties.