Akademik Veri Yönetim Sistemi
Journal of Sol-Gel Science and Technology, cilt.116, sa.1, ss.205-225, 2025 (SCI-Expanded, Scopus)
This study investigates the impact of Se⁴⁺ ion substitution on the electrical and dielectric properties of CoSe3xFe2-4xO₄ (x ≤ 0.1) nanospinel ferrites (Se-CFO NSFs) synthesized via the sol-gel method. DC conductivity measurements show a significant peak at a substitution ratio of x = 0.06, accompanied by a reduction in activation energy, suggesting improved electron mobility. AC conductivity analysis demonstrates both frequency and temperature dependence, with increased conductivity at lower frequencies, attributed to enhanced charge carrier mobility. The dielectric constant and dielectric loss exhibit notable changes at different Se ion substitution levels, with x = 0.06 showing enhanced polarization effects due to Se⁴⁺ incorporation. The dissipation factor is found to be higher at lower frequencies, correlating with an increase in polarization. Complex modulus studies, including Cole-Cole plots, reveal semicircular arcs indicative of multiple relaxation processes, with variations dependent on frequency, temperature, and Se⁴⁺ substitution levels. The ImZ/ReZ ratio as a function of frequency provides detailed insights into the material’s electrical properties, including conductivity and polarization effects, which are influenced by changes in temperature, frequency, and substitution ratio. The Nyquist plot of complex impedance (-ImZ vs. ReZ), measured up to 1.0 MHz at temperatures ranging from 20 to 120°C, and Se substitution levels between 0.02 and 0.10, highlights the behavior of Se-substituted CoFe₂O₄ NSFs. The electrical equivalent circuit model based on R(CR)(QR)(CR) from Cole-Cole impedance functions is thoroughly examined to understand these electrical changes. This extensive analysis offers valuable insights into how Se⁴⁺ ion substitution modifies the structural, electrical, and dielectric properties of CoFe₂O₄ spinel ferrites, highlighting their potential for applications in electronic devices requiring tunable conductivity and dielectric behavior.