Ceramics International, vol.51, no.12, pp.15273-15282, 2025 (SCI-Expanded)
In this study, Co0.25Ni0.25Cu0.25Zn0.25RuxFe2-xO4 (Rux→Co0.25Ni0.25Cu0.25Zn0.25Fe2-xO4) (x ≤ 0.1) nanospinel ferrite (NSFs) were manufactured via sol-gel combustion route, with varying Ru content x ≤ 0.1. The cubic spinel structure was confirmed for all products by XRD analysis. The cubic morphology of the products was confirmed via SEM (Scanning Electron Microscopy), HR-TEM (High Resolution Transmission Electron Microscopy) and TEM (Transmission Electron Microscopy) analyses. The chemical composition of the product has been confirmed by EDX (Energy Dispersive X-ray) analysis. The cation distribution was analyzed using the Bertaut method by comparing observed and calculated intensity ratios of selected X-ray diffraction reflections. The ionic radii of tetrahedral (Td) A-site and octahedral (Oh) B-site cations, theoretical lattice constants, and oxygen positional parameters were determined. Results indicate that Ru substitution leads to a slight expansion in the B-site ionic radius and a subtle increase in the lattice constant, while the A-site configuration remains unaffected. The oxygen positional parameter showed minimal change, indicating structural stability. Additionally, dielectric properties were examined, revealing that the dielectric constant increases with Ru content and T, following Maxwell-Wagner interfacial polarization. AC conductivity analysis indicated thermally activated hopping mechanisms with enhanced polaron hopping due to Ru substitution. Dielectric measurements showed that the dielectric constant increased with Ru content, reaching a maximum of 150,000 at low frequencies for x = 0.10. AC conductivity analysis demonstrated thermally activated hopping mechanisms, with conductivity values increasing from 0.3 S/m for x = 0.00–1.2 S/m for x = 0.10 at 120 °C. This study presents insights into the structural and electrical features of Rux→Co0.25Ni0.25Cu0.25Zn0.25Fe2-xO4 (x ≤ 0.1) NSFs, which could be valuable for magneto-optical applications.