Shielding Effectiveness studies of NiCuZn ferrite-Polyaniline nanocomposites for EMI suppression applications

Electromagnetic interference shielding effectiveness (EMI SE) of multifunctional NiCuZnFe2O4-Polyaniline are studied. The nanocrystalline NCZ-PANI nanocomposites were prepared by the mechanical milling process. The structure and the morphology of the nanocomposites were investigated by Fourier Infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Electromagnetic properties and EMI SE behaviors were performed over a frequency range of 8.2-12.4 GHz (X-band) and 12.4-18 GHz (Ku-band). The results show that for nanocomposites, the values of the real (epsilon') and imaginary permittivity (epsilon '') and imaginary permeability (mu '') increase, while the value of real permeability (mu') decreases as the filler content (PANI) increases. The contributing effects of PANI content on total shielding efficiency (SEtotal) of different samples were investigated. The maximum EMI SE of 29 dB is obtained for a composite of 50 wt.% PANI with the dominant shielding by absorption (SEA) of electromagnetic radiation. The enhanced electromagnetic shielding performance of nanocomposites is attributed to the increment of both magnetic and dielectric losses due to the incorporation of conducting PANI in magnetic NCZ matrix. Synthesis parameters such as the amount and particle size of PANI and NCZ affect significantly the morphology, the conductivity, and the microwave absorption properties of the final materials. The possibility to modulate the electromagnetic properties of the composite materials is of great interest to fabricate microwave absorbing and electromagnetic shielding materials with high performances.