In this study, we examine the negative electromagnetic properties and refractive index in yttrium iron garnet (YIG) -based nanocomposites, specifically Cu10%/YIG and nickel-doped Cu10%/YIG, synthesized via an in-situ method. Field Emission Scanning Electron Microscopy (FESEM) analysis confirmed the successful formation of the target nanostructures. Particle size distribution analysis indicated an approximately normal and uniform distribution across the YIG nanoparticles. UV spectroscopy verified that the electronic structure and optical properties of the samples matched predicted characteristics Measurements of dielectric permittivity and magnetic permeability were conducted at room temperature using scattering parameters from a Vector Network Analyzer (VNA) and processed through MATLAB software. The results showed simultaneous negativity in both ε and μ within certain frequency ranges, confirming the potential for a negative refractive index.This feature opens promising opportunities for advanced electromagnetic wave control, with implications for optical, communication, and electronic technologies.
