Study of structural, magnetic properties and bandgap of spinel Co1−xFe2+xO4 ferrite

Co1−xFe2+xO4 (x = 0.0–0.8) spinel nano ferrite dry gel powders were synthesized by sol gel auto-combustion method. Synthesized samples were investigated by using X-ray diffraction (XRD), magnetic measurements, Ultraviolet–visible (Uv–Vis); Fourier transform infrared (FTIR) spectroscopy. XRD validates the formation of spinel phase, and incorporation of Co, Fe in spinel lattice. Results reveal that compositional variation leads to: i) cationic re-distribution; ii) allowing fine-tuning of bandgap with strong correlation among Bandgap – Fe3+ ions on B-site; iii) changes in degree of inversion; iv) variation of disorder; v) shows better soft magnetic behavior; vi) surface spin disorder leads to reduction of saturation magnetization; vii) observed changes in Debye temperature suggest modification of lattice vibrations.