Enhanced and broadband microwave absorption of flake-shaped Fe and FeNi composite with Ba ferrites

In order to achieve a broad bandwidth absorber at high frequency, the composites of M-type ferrite BaCo_1.0Ti_1.0Fe₁₀O₁₉ (BaM) with flaked carbonyl iron powders (CIP) and flaked Fe₅₀Ni₅₀ were prepared to optimize the surface impedance in broadband frequency, respectively. The diameter of the flaked carbonyl iron powders (CIP) and Fe₅₀Ni₅₀ is in the range of 5–10 µm and 10–20 µm and the thickness of the CIP and Fe₅₀Ni₅₀ is close to 200 nm and 400 nm, respectively. The complex permeability and permittivity show that the addition of BaM obviously reduces the values of real part of permittivity and imaginary part of the permeability which can enhance the matched-wave-impedance. The absorption bands less than −10 dB of CIP-BaM and FeNi-BaM absorber approach to 5.5 GHz (5.7–11.2 GHz) and 7 GHz (11–18 GHz) at 1.5 mm. However, the bands of CIP and FeNi are only 1.9 GHz (4.7–6.6 GHz) and 2.1 GHz (4.0–6.1 GHz). Hence, the electromagnetic match property is greatly improved by BaM ferrites, and this composite shows a broaden absorption band. - Highlights: • In order to achieve a broad bandwidth absorber at high frequency, the composites of M-type ferrite with flaked carbonyl iron powdersand Fe₅₀Ni₅₀ were prepared to optimize the surface impedance. • The complex permeability and permittivity show that the addition of BaM obviously reduces the real part of permittivity and imaginary part of the permeability enhancing the matched-wave-impedance. • The structure, morphology and electromagnetic properties are studied in detail. The optimized properties are ascribed to the strength of dipolar polarization and high frequency magnetic resonance.