The Dispersion Characteristics of the Complex Permeability of NiZnCu Ferrite and its Composite Materials
Rastislav Dosoudil, Marianna Usakova, Elemir Usak, Vladimir Jancarik
DOI:
Abstract
The paper deals with the frequency dependence of complex permeability for the Ni0.27Zn0.63Cu0.1Fe2O4 sintered ferrite produced by conventional ceramic method and its composite materials made of this ferrite (in the form of powder) and non-magnetic polymer matrix (polyvnyl chloride - PVC). The experimental and theoretical curves of the complex permeability were compared. The contribution of both domain wall motion and spin rotational mangetisation processes on th complex permeability in high-frequency region (up to 1 GHz) is discussed. In the case of composite materials, the simple magnetic circuit approach is taken into account. In composites, the real part of the complex permeability in the frequency region above 100 MHz is larger than that of the prepared sintered ferrite. This is attibuted to the shift of the spin and domain wall resonance frequencies toward the higher frequency region by introducing demagnetising fields of magnetic particles in the composite.