Preparation of SiO₂-MnFe₂O₄ composites via one-pot hydrothermal synthesis method and microwave absorption investigation in S-band

MnFe₂O₄ NPs are successfully decorated on the surface of SiO₂ sheets to form the SiO₂-MnFe₂O₄ composite via one-pot hydrothermal synthesis method. The phase identification, morphology, crystal structure, distribution of elements, and microwave absorbing properties in S-band (1.55~3.4 GHz) of the as-prepared composite were investigated by XRD, SEM, TEM, and Vector Network Analyzer (VNA) respectively. Compared with the pure MnFe₂O₄ NPs, the as-prepared SiO₂-MnFe₂O₄ composite exhibits enhanced microwave absorption performance in this frequency band due to the strong eddy current loss, better impedance matching, excellent attenuation characteristic, and multiple Debye relaxation processes. The maximum reflection loss of −14.87 dB at 2.25 GHz with a broader −10 dB bandwidth over the frequency range of 1.67~2.9 GHz (1.23 GHz) can be obtained at the thickness of 4 mm. Most importantly, the preparation method used here is relatively simple, hence such composite can be served as a potential candidate for effective microwave absorption in S-band.