Electromagnetic wave absorption properties of conducting polymer-spinel ferrite composites

Electromagnetic interference (EMI) is an undesirable and uncontrolled off-shoot of tremendous growth of electronics and widespread use of transient power sources. A novel class of nanocomposites such as spinel ferrite-conducting polymer composite that possess unique combination of electrical, dielectric and magnetic properties can be significantly used for the suppression of electromagnetic interference. The spinel ferrite synthesis is carried out through sol-gel mediated auto-combustion method. Ferrimagnetic nanostructured spinel ferrites are mixed with conducting polymer for the enhancement of electromagnetic (EM) wave absorption with wide bandwidth of absorption along with the added advantage of flexibility, adhesive nature and light weight of the composite. Complex permittivity and permeability of the synthesized materials are calculated with the help of Vector Network Analyzer (VNA) in the frequency range 2-18 GHz and the corresponding reflection loss is computed. The polymeric matrix PANI shows 7 GHz broad bandwidth of absorption -10 dB. Composites of spinel ferrites with PANI enhances the EM wave absorption properties of both nickel ferrite and nickel zinc ferrite. Nickel zinc ferrite with PANI shows significant enhancement in absorption for C-band (4-8 GHz), whereas nickel ferrite with PANI shows better reflection loss in Ku-band (12-18 GHz). Nickel zinc ferrite-PANI gives -10 dB bandwidth of 8.5 GHz and nickel ferrite with PANI shows maximum reflection loss of -17.44 dB at frequency of 12.25 GHz with bandwidth of 3.68 GHz.