Enhancement in the electromagnetic shielding properties of doped M0.01Fe2.99O4 magnetite nanoparticles (M = Mn2+, Ni2+, Cu2+, Zn2+)

Abstract

<p>Fe3O4 nanoparticles (NPs) are one of the most investigated materials in the field of microwave absorbers. To further optimize the electromagnetic interference (EMI) shielding effectiveness, doped M0 .01Fe2.99O4 (M = Mn, Ni, Cu, Zn) NPs were synthesized through co-precipitation method. All samples were subjected to X-ray diffraction analysis to determine their crystal structure. Transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy were performed to confirm the morphologies, distribution of elements, and valence of iron in the prepared nanoparticles, respectively. The dielectric and magnetic characteristics displayed a considerable improvement for the doped Fe3O4 samples, except Zn0.01Fe2.99O4 where the obtained values were found to be comparable to those of pure Fe3O4. These variations are described in terms of the homogeneously distributed microstructure, mixed spinel cationic distribution in the doped samples, and Fe+/Fe 2 3ratios at the octahedral interstitial + sites. Moreover, the EMI shielding efficiency was measured in the X-band frequency range (8.2 - 12.4 GHz) using a wave guide approach. The total shielding effectiveness of Cu0.01Fe2.99O4 and Ni0.01Fe2.99O4 samples was found to be much higher than that of pure Fe3O4 with absorption being the dominant mechanism. This is most likely owing to their high dielectric permittivity, enhanced conductivity, and high magnetic permeability, which results in improved impedance matching and stronger microwave absorption. This suggests that these doped nanoparticles may be utilized as efficient electromagnetic absorbers.</p>