Investigation of structural, magnetic and microwave absorption properties of NixCo1-xFe2O4/Ni:ZnO (x:0.0, 0.5, and 1.0) embedded epoxy composites

In this study, Ni x Co 1−x Fe 2 O 4 /Ni:ZnO (x:0.0, 0.5, and 1.0) epoxy-based composite structures were manufactured by sol–gel method. The structural, morphological and magnetic characteristics were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). Electromagnetic wave (EMW) absorption measurements were carried out using a vector network analyzer (VNA) between 8 and 12 GHz (X band). Ni substitution with Co decreases the crystallite size, average particle size, magnetic saturation ( M s ) and the coercive field ( H c ) values of cobalt-ferrite spinel structure. EMW characterization results showed that minimum reflection loss (RL) − 30.91 dB (99.9% absorption) at 10.76 GHz, and the maximum bandwidth of 1.81 GHz were observed for the RAM1 composite. In addition, the substitution of Ni 2+ into the cobalt–ferrite structure resulted in the shifting absorption peaks to the higher frequency region (towards K u band).