Synthesis, structural and magnetic properties of cadmium substituted Li-ferrite

We present study of Li_0.5-x/2Cd_xFe_2.5-x/2O₄ (thermally treated at 450 °C for 3 hours) nano crystalline ferrites, synthesized by sol-gel auto-combustion method. X-ray diffraction (XRD), magnetic measurements were used to probe the structural, magnetic properties. Results show that successive Cd²⁺ addition leads to: i) formation of nano-crystalline phase (Williamson-Hall grain diameter D_W-H range between 16.0 nm – 63.6 nm). Slight presence of α-Fe₂O₃ phase was also observed, ii) changes in experimental lattice parameter a_exp (range between 0.8321 nm – 0.8373 nm), obtained cell volume (V), specific surface area (S), X-ray density (ρ_XRD), are ascribed to the difference in ionic radii of Fe³⁺, Cd²⁺, Li¹⁺ ions; and Cd²⁺ ions migrate predominantly to A-site (thus pushing Fe³⁺ ions on B site) leading to increased distortion in the lattice displayed by increase of oxygen parameter (u) from 0.3797 to 0.3849, iii) migration of cations leads to changes in saturation magnetization M_s (varies between 52.7 Am²/kg – 61.7 Am²/kg), whereas coercivity H_c varies between 111.09 Oe−150.04 Oe, iv) formation of softer magnetic material with minimum losses of 1.61 J/kg, v) linear variation of H_c with grain diameter, reveals that the studied samples lie in the region with overlap between single or multi-domain region. Current study clearly shows strong correlation between structural, magnetic properties.