Cation Redistribution and Defect Suppression in Zn‐Doped CuFe 2 O 4 Ferrites: Structural, Optical, and Magnetic Correlations

Cu 1− x Zn x Fe 2 O 4 (0.0 ≤ x ≤ 1.0) nanoparticles were synthesized via a PEG‐assisted combustion route to elucidate the influence of Zn substitution on structural, optical, and magnetic properties. X‐ray diffraction (XRD) confirmed a transition from multiphase CuFe 2 O 4 to a single‐phase normal spinel ZnFe 2 O 4 , accompanied by lattice expansion and crystallite growth. Fourier transform infrared (FTIR) analysis revealed progressive cation redistribution and strengthening of tetrahedral AO bonds, while UV–Vis spectra exhibited bandgap widening (1.35–2.03 eV) and defect suppression. X‐ray photoelectron spectroscopy (XPS) further validated the dominant Fe 3+ and Zn 2+ oxidation states and revealed weak Cu 2 p features consistent with low Cu content or mixed‐valence species, confirming the expected chemical environment of Zn‐substituted Cu ferrites. Vibrating sample magnetometer (VSM) studies showed soft ferrimagnetism with maximum magnetization at x ≈ 0.2–0.4 due to Fe 3+ migration to B‐sites, followed by a decline at higher Zn from A‐site dilution and spin canting. The cation inversion model ( p ≈ 0.32) successfully reproduced the Bohr magnetons per formula unit ( μ B /f.u.) trend. Zn substitution thus stabilizes the spinel lattice, enhances structural order, and enables tunable optical and magnetic functionalities, making Cu–Zn ferrites promising for multifunctional spintronic and optoelectronic applications.