Synthesis and magnetic properties of lanthanum-substituted lithium-nickel ferrites via a soft chemistry route

A rheological phase reaction method was developed to synthesize the nanocrystalline lanthanum-substituted lithium-nickel ferrites, Li0.25Ni0.5LaxFe2.25−xO4 (x=0.00, 0.025, 0.05, 0.075, 0.10). The structure, morphology, and magnetic properties of the as-prepared Li0.25Ni0.5LaxFe2.25−xO4 ferrites were characterized by powder X-ray diffractometer (XRD), scanning electron microscope (SEM), and vibrating sample magnetometer (VSM). It was shown that Li0.25Ni0.5LaxFe2.25−xO4 ferrites exhibited the single-phase spinel structure. The lattice parameters increased with increasing the La content, whereas the crystallite sizes decreased. The magnetic properties of Li0.25Ni0.5LaxFe2.25−xO4 ferrites were strongly affected by the La content. The saturation magnetization decreased, while coercivity increased with increasing the La content.