Dielectric properties of barium hexaferrite in the microwave range

摘要

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