SAIP2026

Multifunctional Rare-Earth Doped Spinel Ferrites: From Structural, Magnetic Tuning, and Functional Application

7 Jul 2026, 10:10

20m

Lecture Hall GH1 (University of the Western Cape)

Oral Presentation Track A - Physics of Condensed Matter and Materials Physics of Condensed Matter and Materials

Speaker

Nkanyiso Linda Ndlovu (Discipline of Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa)

Description

Rare-earth (RE) doped spinel ferrite nanoparticles (RE-MFe2O4, where M = Co, Ni, Zn) provide a versatile platform for tailoring structural, magnetic, and surface properties at the nanoscale. In this work, we present a systematic investigation of the structure–magnetism–function relationships in RE-doped spinel ferrites synthesized via controlled wet-chemical routes, to develop multifunctional materials for gas sensing and bio-relevant magnetic nanomaterials. X-ray diffraction (XRD) confirms the formation of single-phase cubic spinel structures, with lattice expansion governed by the ionic radius and preferential site occupancy of the rare-earth dopants. Transmission electron microscopy reveals narrowly distributed crystallite sizes in the range of approximately 10 - 25 nm, accompanied by controlled surface defect densities that are critical for functional performance. Magnetic characterization using field-dependent magnetization (M-H) and temperature-dependent measurements (ZFC/FC) demonstrates enhanced coercivity and modified magnetic exchange interactions arising from RE-induced redistribution of Fe3+ ions between tetrahedral (A) and octahedral (B) sites. These modifications lead to tunable ferrimagnetic ordering and increased surface spin disorder. The resulting magnetic and structural changes directly influence functional behaviour. In particular, gas sensing measurements toward oxidizing and reducing analytes show that rare-earth substitution enhances the density of chemisorbed oxygen species and modulates charge-transfer kinetics at the surface. Consequently, the RE-doped ferrites exhibit improved sensing sensitivity, reduced operating temperatures, and faster response recovery dynamics. Overall, the results establish a coherent structure, magnetism, and function framework across compositions, demonstrating that rare-earth substitution acts as an effective design strategy for engineering multifunctional magnetic oxide nanomaterials. This integrated approach highlights spinel ferrite nanoparticles as scalable candidates that bridge magnetic materials science with sensing technologies and emerging bio-related applications.