Effect of Ni substitution content on structure and magnetic properties of spinel ferrites synthesized from laterite leaching solutions

Abstract A series of Ni x Mg 0.955− x Co 0.005 Mn 0.04 Fe 2 O 4 ( x =0.13, 0.40, 0.65, 0.85 and 0.90) were synthesized from laterite leaching solutions with different adding amounts of NiCl 2 ·6H 2 O by using a coprecipitation–calcination method. The as-prepared samples were characterized by X-ray diffraction (XRD) and Physical Property Measurement System (PPMS) to determine the structures and magnetic performance. It is shown that all the samples were single phase of cubic spinel ferrites. With Ni substitution content increasing from 0.13 to 0.90, the lattice constant decreased from 0.8347 to 0.8328 nm, and the average grain size varied from 37.90 to 50.59 nm, respectively. Meanwhile, the saturation magnetization (Ms) and the coercivity (Hc) values gradually increased from 29.6 to 41.0 emu g −1 , and from 55 to 75 Oe, accordingly. The enhancement of saturation magnetization can be well explained by Neel׳s two sublattice models.