Structural and magnetic properties of nickel ferrite nanoparticles synthesized via a template-assisted sol–gel method

Spinel nickel ferrite (NiFe 2 O 4 ) nanoparticles with high specific area and excellent magnetic properties were synthesized via a template-assisted sol – gel method. The effects of template type on the structural properties, magnetic properties, and heating rate are investigated. Results of XRD and TEM indicate that the NiFe 2 O 4 particles synthesized using templates exhibit a typical single phase spinel structure in nano size. The sample using sponge or cotton as template presents the best saturation magnetization (66.6 emu/g) and the lowest coercivity (137.7 Oe), respectively, and their specific surface area is enhanced greatly from 20.1 m 2 /g to 55.7 m 2 /g. It is found that the calculated hysteresis loss agrees well with the measured radio frequency heating rate.