Synthesis and characterization of thermally treated Co_1-xFe_2+xO₄ (x = 0.0 –0.8) spinel nano ferrite

We report the effect of surplus-Fe-content, and thermal annealing on properties sol gel auto-combustion synthesized Co 1–x Fe 2+x O 4 (x = 0.0–0.8) spinel ferrites. X-ray diffraction (XRD), magnetic measurements, Fourier transform infrared (FTIR) spectroscopy, Ultraviolet–visible (UV–Vis) are used to monitor excess Fe-content, dependence properties, correlation among them. XRD validates presence nanoferrite (31.54 – 44.89 nm) phase, minor α-Fe 2 3 phase was also detected. Results reveal that variation Fe-content leads to: i) lattice-parameter, re-distribution 3+ . 2+ ions A, B-site, ii) alteration inversion degree, disorder, iii) modification saturation magnetization due spin disorder at surface, iv) coercivity, related grain size imply studied ferrites in single-multi domain overlap regions, while squareness-ratio indicates inter-grain interaction, isotropic behaviour multi-domain particles; fine-tuning bandgap (1.35 1.5 eV) via changes cationic-distribution v) Debye temperature, suggests lattice vibrations. Current work implies strong between magnetic, structural properties.