Synthesis and magnetic properties of NiFe2−xSmxO4 nanopowder

NiFe2−xSmxO4 (x=0.00, 0.05, 0.10 and 0.15) nanopowders were synthesized via a sol-gel combustion route. The structural studies were carried out by X-ray diffractometer, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. The XRD results confirmed the formation of single-phase spinel cubic structure. The crystallite size decreased with an increase of samarium ion concentration, while lattice parameter and lattice strain increased with samarium substitution. TEM micrographs showed that agglomerated nanoparticles with particle sizes ranging from 35 to 90 nm were obtained. The magnetic studies were carried out using vibrating sample magnetometer. Magnetic measurements revealed that the saturation magnetization (Ms) of NiFe2−xSmxO4 nanoparticles decreases with increasing Sm3+substitution. The reduction of saturation magnetization is attributed to the dilution of the magnetic interaction. The coercivity (Hc) of samples increases by adding samarium.