Optical analysis of ferrite films using spectroscopic ellipsometry.

This article focuses on the optical properties of nickel zinc ferrite (NZF), nickel copper zinc ferrite (NCuZF), and nickel cobalt zinc ferrite (NCoZF) thin films prepared on Si/SiO₂ substrates via sol-gel and spin-coating techniques, followed by annealing at 500 and 800 °C. Using a J.A. Woollam Company RC2 model D variable angle spectroscopic ellipsometer, the study measured amplitude ratio (Ψ) and phase difference (Δ) spectra at multiple incident angles across 190–1000 nm to extract key optical parameters such as refractive index and extinction coefficient through modeling with Kramers–Kronig consistent oscillators and the Bruggeman effective medium approximation for surface roughness. Results indicate that doping NZF with copper or cobalt alters the optical constants, with NCuZF films exhibiting the highest refractive indices and extinction coefficients, and annealing temperature influencing these properties differently across the materials. The detailed optical characterization provided supports potential applications of these ferrite films in optoelectronic devices, including solar cells.