Fabrication, structure, and microwave absorbing properties of plate-like BaFe12O19@ZnFe2O4/MWCNTs nanocomposites

Abstract

In order to reduce the radiation and interference of electromagnetic waves, rational assembly of dielectric materials and magnetic materials is becoming a promising strategy to produce highly efficient microwave absorbers. Herein, a novel kind of ternary nanocomposites, multi-wall carbon nanotubes decorated plate-like BaFe12O19@ZnFe2O4 (BaFe12O19@ZnFe2O4/MWCNTs), was fabricated via a two-step method. Plate-like BaFe12O19 was prepared firstly as a template for the growth of ZnFe2O4 layer, forming a core-shell structure. MWCNTs dispersed between BaFe12O19@ZnFe2O4 particles and ZnFe2O4 microspheres, forming three-dimensional (3D) conductive networks. The careful design of the structure and the combination of the dielectric material with the hard-soft magnetic material caused excellent impedance matching and multiple loss mechanisms, which endow the ternary hybrids with remarkable microwave absorption performance. The minimum reflection loss reaches −42.3 dB at 8.2 GHz with a layer thickness of 2.5 mm, and the effective bandwidth is 3.6 GHz (from 12.5 GHz to 16.1 GHz) with a layer thickness of 1.5 mm.