Microwave absorbing properties of barium hexa-ferrite/polyaniline core-shell nano-composites with controlled shell thickness

Barium hexa-ferrite (BaFe12O19)/polyaniline (PANI) core-shell nano-composites have been fabricated by an in situ polymerization and the shell thickness of PANI layers were tuned by increasing the content of the starting monomer and evaluated by combination TG and TEM results. Based on these, the influences of the shell thicknesses on the properties of the as-synthesized nano-composites have been investigated. The results indicated that the electric and magnetic characteristics of the synthesized nano-composites have been tuned by altering the shell thickness. With refining impedance match and taking advantages of conductance loss, magnetic resonance loss and interfacial loss, the microwave absorbing properties of the synthesized composites have been enhanced. Both the microwave absorbing efficiency and frequency range changed as the shell thickness increased. The optimized core-shell nano-composites with the shell layer of 30-40 nm demonstrated the best microwave absorbing properties with the maximum absorption −28 dB at 12.8 GHz and the −10 dB absorption bandwidth of 3.8 GHz (11.8 GHz-15.6 GHz) as the thickness of the absorbing layer was as thin as 2.0 mm.