Electromagnetic properties of hybrid polymer composites

The effective permeability of a composite material is studied experimentally and theoretically. The composite material has a core-shell-like structure, where the core is a ferromagnetic particle and the shell is a conductive overlayer. It is established that the conducting layer partially shields the magnetic particle and changes the effective magnetization of the said particle. As a result, there is a change of the effective permeability of the hybrid composite. It is shown that both the permeability and the ferromagnetic-resonance frequency of a hybrid copmosite can be changed by the controlled overlayer conductivity and the selection of a relation between the thickness of the layer and the size of the magnetic particle.