DC bias-dependent dielectric response and superlinear AC conduction in nanocrystalline Mn–Zn spinel ferrites

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dc.contributor.authorBouchelaghem, A.Z.
dc.contributor.authorGokcen, M.
dc.contributor.authorKurnaz, S.
dc.contributor.authorVarilci, A.
dc.contributor.authorOzturk, O.
dc.contributor.authorAltintas, S.P.
dc.date.accessioned2026-07-01T11:36:26Z
dc.date.available2026-07-01T11:36:26Z
dc.date.issued2026
dc.departmentDüzce Üniversitesi
dc.description.abstractThis study investigates the structural, morphological, and electrical properties of nanocrystalline Mn0.9​Zn0.1​Fe2−x​Lax​O4​ (x=0.00, 0.05, 0.10, and 0.15) ferrites synthesized via the co-precipitation method. X-ray diffraction (XRD) patterns confirm the formation of a single-phase cubic spinel structure for all compositions. Structural parameters, including lattice constant and unit cell volume, initially decrease with La substitution up to x=0.10, followed by a slight expansion at x=0.15. The crystallite size reaches a minimum of 6.9 nm at the x=0.10 threshold, reflecting a state of maximum lattice distortion. Magnetic measurements reveal near-superparamagnetic behavior with dominant thermally assisted moment relaxation, as evidenced by squareness ratios far below the single-domain limit (Mr/Ms ≈ 0.04–0.05), with saturation magnetization showing a sharp minimum at x = 0.10 and partial recovery at x = 0.15. The dc bias–dependent dielectric and electrical properties of the samples were investigated by complex impedance spectroscopy in the 1 kHz–10 MHz frequency range under 0–40 V bias. Nyquist analysis revealed a near-ideal yet non-Debye relaxation characterized by high Cole–Cole α values (0.88–0.95), indicating grain-boundary-dominated charge dynamics. The x = 0.10 composition exhibited reduced grain resistance, suggesting a critical substitution level for enhanced charge transport. AC conductivity followed Jonscher's power law but displayed a systematic superlinear frequency exponent (1.23 ≤ s ≤ 1.36) for all compositions and bias voltages. The persistence of s > 1 confirms the emergence of a Superlinear Power-Law (SLPL) regime, deviating from the conventional sublinear response typically reported for Mn–Zn ferrites. The superlinear behavior, observed even in the undoped sample, is attributed to intrinsic nanostructural disorder and localized carrier dynamics. These results highlight the role of defect structure and microstructural heterogeneity in governing high-frequency charge transport in spinel ferrites. © 2026 Elsevier Ltd and Techna Group S.r.l. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
dc.identifier.doi10.1016/j.ceramint.2026.05.191
dc.identifier.issn0272-8842
dc.identifier.scopus2-s2.0-105040706998
dc.identifier.scopusqualityQ1
dc.identifier.urihttps://doi.org/10.1016/j.ceramint.2026.05.191
dc.identifier.urihttps://hdl.handle.net/20.500.12684/23027
dc.indekslendigikaynakScopus
dc.language.isoen
dc.publisherElsevier Ltd
dc.relation.ispartofCeramics International
dc.relation.publicationcategoryMakale - Uluslararası Hakemli Dergi - Kurum Öğretim Elemanı
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.snmzKA_Scopus_20260623
dc.subjectAC conductivity
dc.subjectDielectric properties
dc.subjectLanthanum substitution
dc.subjectSpinel ferrites
dc.subjectSuperlinear power-law (SLPL)
dc.titleDC bias-dependent dielectric response and superlinear AC conduction in nanocrystalline Mn–Zn spinel ferrites
dc.typeArticle

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