Rare earth Ce and Y cation co-substitution and its effects on the strain, elasticity, and magnetism of Co-Zn ferrite nanomaterials

This study investigates the structural, elastic, and magnetic properties of Ce 3+ and Y 3+ co-substituted Co 0.85 Zn 0.15 Fe 2-2x O 4 spinel ferrite to understand the influence of rare-earth ion incorporation on the material's overall performance. The samples were synthesized using the sol-gel auto-combustion method, and their phase purity, crystallinity, and structural parameters were confirmed using X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy. The XRD analysis revealed a single-phase cubic spinel structure with a systematic increase in lattice constant and crystallite size as Ce 3+ and Y 3+ concentrations increased, attributable to the larger ionic radii of the substituents. FTIR spectra exhibited shifts in metal-oxygen stretching vibrations, indicating lattice expansion and bond stiffness variations. Strain analysis using Williamson-Hall and Size-Strain Plot methods revealed increased microstrain and crystallite size with higher dopant levels, suggesting lattice distortions. Elastic parameters, including stiffness constant, bulk modulus, and Young's modulus, improved with increasing rare-earth content, indicating enhanced mechanical stability. Conversely, magnetic measurements demonstrated a reduction in saturation magnetization, coercivity, and anisotropy due to magnetic sublattice dilution, lattice strain, and weakened superexchange interactions. These results highlight that rare-earth co-substitution is an effective strategy to tailor the structural and mechanical properties of Co-Zn ferrite, though with a trade-off in magnetic performance, offering a pathway to customize these materials for advanced technological applications.