Effect of Mn2+ and Cd2+ on the Physical Properties of Li-Mixed Spinel Nanoferrites

The mixed Li-ferrites with dopants Mn2+ and Cd2+ are synthesized by chemical co-precipitation method. Structural and morphology analysis with X-ray diffraction (XRD) and SEM, respectively, confirmed the spinel structure with uniform distribution of the nanoparticles of the size in the range 17–36 nm. The dopant concentration affects the lattice parameter by incorporating Cd2+, lattice parameter increases in the range 8.3–8.7 Å. This increase is attributed due to difference in ionic radii of cations. The dc electrical resistivity (ρ dc) and drift mobility (μ d) confirmed a semiconducting-like behavior. The increase in dopant concentration decreases the activation energy (ΔE). A small amount of Cd2+ causes a sudden increase in saturation magnetization (M s) and remanence (M r) values. It is observed that up to x=0.30 M s increases, while further incorporation of Cd2+ decreases magnetization. This is due to canted spin and can be explained on the basis of the canted spin model. The decrease in Curie temperature with increase in Cd2+ is due to interaction between tetrahedral (A) and octahedral (B) lattice sites.