Dielectric properties of barium hexaferrite in the microwave range

The charge carriers that are responsible for propagating current through a material have different behaviours for different applied frequencies, especially for high frequency applications. It is important to understand the role of several contributing factors. In view of the different applications of ferrites at microwave frequencies, this work is specially devoted to the study and the understanding of the transport mechanism in barium hexaferrite in the 1 MHz to 2 GHz range. In this range of frequencies complex electrical permittivity (/spl epsiv/', /spl epsiv/") and complex magnetic permeability (/spl mu/', /spl mu/") were analyzed. The particles of barium hexaferrite were synthetised by a new chemical coprecipitation method, that provided small particles (<0,5 /spl mu/m) with very good magnetic properties. By this new preparation method, we obtained the hexagonal ferrite at relative low temperatures (800/spl deg/C), so we can modify grain size with temperature up to 1200/spl deg/C. It is known that different sizes contribute differently to dielectric response in frequency. The Jonscher universal dielectric response theory is applied to evaluate the experimental results.