Facile synthesis and enhanced microwave absorption of C@Ni0.5Zn0.5Fe2O4 shell-core structured nanoparticles

Abstract

C@Ni0.5Zn0.5Fe2O4 nanoparticles with different annealing temperatures and shell-core mass ratios were synthesized by a tannic acid coating method. Through SEM, TEM, EDS and XRD characterization, the as-prepared product was confirmed to be shell-core structured C@Ni0.5Zn0.5Fe2O4 nanoparticles with an average diameter of approximately 650 nm, and a carbon layer was deposited on the surface of the product. Compared with uncoated NiZn ferrite, the carbon-coated NiZn ferrite exhibits a moderate real part and imaginary part of its complex permittivity, while maintaining high permeability, which improves the impedance matching characteristics and microwave loss performance of the material. When the shell-core mass ratio was 9:1 and the annealing temperature was 900 °C, the as-prepared sample exhibited advanced microwave absorption performance with a minimum reflection loss (RL) of -26.87 dB at 4.3 GHz with a matching thickness of 1.8 mm, and the effective absorptive bandwidth was approximately 4.05 GHz when the RL was below -10 dB.