Abstract

In this research, iron–cobalt nanoparticles and iron–cobalt@polyaniline (FeCo@PANI) nanocomposite was prepared using two-step process including polyol process and in situ chemical oxidative polymerization. X-ray diffraction confirms the formation of FeCo alloy. As seen in VSM results FeCo@PANI nanocomposite leading to lower saturation magnetization and higher natural-resonance frequency than FeCo alloy. The effect of various parameters including solvent type, NaOH amount, sugar amount, sugar type, Fe/Co ratio and precursor type on the magnetic properties of prepared FeCo alloy have been investigated in details. The electromagnetic absorption characteristics of nanoparticle and nanocomposite were determined in the frequency range of 8–18 GHz. Results show that the PANI improves electromagnetic wave absorption properties of FeCo nanoparticles. The main mechanism enhancing the dielectric loss tangent is Deby’s dual relaxation phenomenon and for magnetic loss is the ferromagnetic resonance. The maximum reflection loss of − 5.48 dB was obtained for 40 wt FeCo@PANI nanocomposite with an effective absorption band (RL < − 3 dB) of 1.22 GHz. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.