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    Cation distribution and Electrical/Dielectric features of Ru substituted CoNiCuZn spinel ferrite nanoparticles
    (Elsevier Ltd, 2025) Almessiere, Munirah A.; Shirsath, S. E.; Baykal, A.; Mihmanlı, Ahmet; Gondal, M. A.; Slimani, Yassine
    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 MaxwellWagner 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 magnetooptical applications.
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    Exploration of electrical and dielectric properties of Ho‑substituted SrBa‑hexaferrite/Ni‑spinel ferrite nanocomposites
    (SPRINGER, VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS, 2024) Ünal, Bayram; Baykal, Abdülbaki; Almessiere, Munirah Abdullah; Manikandan, Akshay; Slimani, Yassine; Ul-Hamid, Anwar
    Hard/soft Sr0.5Ba0.5HoxFe12−xO19/NiFe2O4 nanocomposites (H/S Ho-SBF/NFO (x ≤ 0.08) NCs) have been synthesized via a one-pot sol–gel combustion route. X-ray powder difraction analysis confrmed the formation of both cubic and hexagonal structures and nano size of all samples. The chemical compositions of the products were followed via Energy Dispersive X-ray spectroscopy (EDX). This study systematically explores the dielectric and electrical properties of H/S Ho-SBF/NFO (x ≤ 0.08) NCs, where the Ho3+ ion doping ranges from 0.00 to 0.08. Measurements encompassed up to 3.0 MHz and between 20 and 120 °C. The investigation includes an in-depth analysis of ac/dc conductivity, dielectric constant, dielectric loss, dissipation factor, and real and imaginary modulus (ImM) across the entire range of Ho3+ ion substitution ratios. Results demonstrate that conductivity variations exhibit power law dynamics relative to frequency (f), predominantly infuenced by Ho3+ ion substitutions in the NCs. The f-dependent behavior of the dielectric constant across all NCs underscores its sensitivity to the substitution ratio “x”, with most dielectric parameters atributed to interactions between grains and grain boundaries. These fndings align with conduction mechanisms typical in compositional ferrites, consistent with Koop’s model.
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    Exploring dielectric and electrical characteristics in Sr0.5Ba0.5SnxFe12-xO19/CoFe2O4 nanocomposites
    (ELSEVIER SCI LTD, 125 London Wall, London EC2Y 5AS, ENGLAND, 2024) Almessiere, Munirah Abdullah; Ünal, Bayram; Baykal, Abdulhadi; Demir Korkmaz, Ayşe; Gondal, Mohammed Ashraf; Slimani, Yassine; Kahraman, Süleyman; Güngüneş, Hakan
    This study examined the morphological, structural, electrical, and dielectric characteristics of hard-soft (H-S) Sr0.5Ba0.5SnxFe12-xO19/CoFe2O4 (x ≤ 0.10) ferrite nanocomposites (NCs), created using one-pot sol-gel combustion route. This study systematically investigated the electrical/dielectric features of H-S Sr0.5Ba0.5SnxFe12- xO19/CoFe2O4 NCs where x is within the range of 0.00 ≤ x ≤ 0.10. The examination realizes frequencies that reach 3.0 MHz, conducted within 20 ◦C–120 ◦C. A detailed analysis was performed to investigate various conduction mechanisms linked with dielectric constant, dissipation factor, AC/DC conductivity, loss of dielectric capacity, and real/imaginary modulus, which were explored across the entire range of Sn ion substitution ratios. Observations reveal that the conductivity variations adhere to power law dynamics concerning frequency, predominantly influenced by the Sn ion substitution ratios within the NCs. Furthermore, the frequency dependency of the dielectric coefficient across all NCs substantiates the common propagation of dielectric behavior, prominently contingent upon the substitution ratio of "x". Notably, the majority of dielectric parameters observed in H-S Sr0.5Ba0.5SnxFe12-xO19/CoFe2O4 (x ≤ 0.10) NCs are attributable to grain-to-grain boundaries, elucidated by conduction mechanisms similar to those observed in most compositional ferrites, explicable through Koop’s model.