Copper/yttrium iron garnet (Cu/YIG) nanoparticles (NPs) were prepared by sol-gel method to elucidate the Cu content on the structural, electrical and magnetic behaviors of NPs. Analysis of the structural properties was performed using XRD and shows that all samples have a single cubic crystal structure with general formula A3B5O12. The complex permittivity (ɛ), complex permeability (μ) and S-parameter were determined at room temperature as a function of frequency. For high amounts of copper, the dielectric loss is dominated by conduction and polarization. Results indicate that conduction occurs through the grain boundaries in these samples. The complex permeability measurements at room temperature conclude that the permeability decreases with Cu adding, which may be due to the difference in magnetic moment of Cu and Fe ions. The Cu/YIG nanocomposites with tunable negative dielectric constant have great potential in the field of electromagnetic damping, shielding and antenna.
