Abhishek Kumar, Hara Mohan Jena
This study addresses the lack of systematic comparative data on spinel ferrite nanoparticles synthesised under identical coprecipitation conditions by preparing CoFe₂O₄, NiFe₂O₄, CuFe₂O₄, and ZnFe₂O₄ nanoparticles and evaluating their structure-property relationships. The samples were characterised using XRD, FTIR, FESEM, DLS, zeta potential, TGA, and VSM. XRD confirmed the formation of highly crystalline cubic spinel phases with crystallite sizes in the range of 15.20–27.6 nm. FTIR analysis verified spinel metal-oxygen vibrations, while FESEM revealed agglomerated nanoscale morphologies with composition-dependent surface differences. DLS and zeta potential measurements indicated distinct hydrodynamic sizes and colloidal behaviour, with CoFe₂O₄ showing comparatively better colloidal stability among the studied ferrites, as indicated by its higher absolute zeta potential value (-25.04 mV). Thermal analysis demonstrated superior thermal resistance for CoFe₂O₄ relative to the other ferrites. Magnetic characterisation showed a clear dependence on composition, with CoFe₂O₄ exhibiting the highest saturation magnetisation (48.49 emu/g), followed by NiFe₂O₄, CuFe₂O₄, and ZnFe₂O₄. The study establishes a comparative structure-property framework for spinel ferrites synthesised through the same route and identifies CoFe₂O₄ as the most balanced multifunctional material for applications requiring magnetic response, colloidal stability, and thermal robustness.