Development of least sized magnetic nanoparticles with high saturation magnetization

Magnetic nanoparticles of high saturation magnetization with least particle size are essential candidates for certain biomedical applications like hyperthermia. The development of such nanoparticles requires stringent processing conditions in arriving at desired characteristics. Magnesium substituted cobalt ferrite nanoparticles of size around 4 nm were processed by sol-gel method with high saturation magnetization and characterized by techniques XRD, TEM, FESEM and FTIR in elucidating the structural parameters. Magnetic properties were discussed in terms of a proposed cation distribution and occupancy of magnesium was established from electrical resistivity measurements. •CoMg ferrite nanoparticles with size 4.0–8.2 nm are synthesized by sol-gel method.•The chelating agent adequately controls the particle size.•High saturation magnetization has been achieved for these particles.•Magnetic properties have been discussed in terms of a proposed cation distribution.•The study establishes the occupancy of magnesium ions at octahedral sites.