Electrophysical properties of polymeric nanocomposites based on cobalt and nickel ferrites modified with copper iodide

•The possibility to obtain composites with adjustable dielectric and magnetic permeability in the microwave range.•Used a simple method of synthesis for the production of composite materials.•The optimum content of the copper iodide in the composites was identified experimentally. Cobalt and nickel ferrites modified with copper iodide were synthesized by the sol-gel autocombustion method. An optimum content of the copper iodide (~0.38 by volume) in the composites of CuI/CoFe2O4 and CuI/NiFe2O4, which leads to the most intensive and maximum values of electrical parameters was identified experimentally. Magnetic and electrophysical properties of CuI/ferrite filled polychlorotrifluoroethylene (PCTFE) composites were examined at low frequencies and in the microwave range at ambient temperature. For polymer composites with modified cobalt ferrite, the values of the real and imaginary components of the complex permittivity at a frequency of 9 GHz are 3–5 times higher than for composites with modified nickel ferrite. The values of electrical conductivity at a frequency of 100 Hz for polymer composites with modified cobalt ferrite are 1–2 orders of magnitude higher than for composites with modified nickel ferrite.