Microwave characteristics of Co/TiO2 nanocomposites prepared by mechanochemical synthesis

Co/TiO2 nanocomposites were prepared by mechanochemical synthesis. The microwave characteristics of the Co/TiO2 nanocomposite–paraffin wax mixture were studied in the 0.1–18 GHz frequency range. The measured relative complex permittivity of the Co/TiO2 nanocomposite–paraffin wax mixture indicates a higher electrical resistivity of the Co/TiO2 nanocomposites compared to the pure Co. The imaginary part of the relative complex permeability of the mixture exhibits a broad resonance peak at 5.1 GHz which results from the natural resonance of Co. The Henkel plots confirm that the magnetic dipolar coupling interaction between the Co grains in the nanocomposites leads to the shift of resonance peak to a lower frequency. The calculated reflection loss curves show that the minimum reflection loss value of the Co/TiO2 nanocomposite–paraffin wax mixture can reach −27 dB at 3.5 GHz with 3 mm sample thickness.