Monodispersed superparamagnetic FeO4 nanoparticles: synthesis and characterization.
Monodispersed Fe3O4 (magnetite) nanoparticles are synthesized by non-aqueous thermal decomposition route. The powder XRD reveals single phase spinel structure with 60 angstroms particle size. The TEM image shows nearly monodispersed spherical particles with log-normal median diameter of 49 A and size distribution in In(D) 0.12. The monodispersivity is also confirmed by SANS experiment. TGA pattern shows a sharp single step transition at 606 K indicating a monolayer coating of the oleic acid on particle surface. Temperature dependent low field dc magnetization study suggest that particles are superparamagnetic above 25 K with an effective blocking temperature 12 K @ 50 Oe field, indicating the dominance of particle-particle interaction in the system. The saturation magnetization of the nanocrystals, M(s), at 5 K is very close to that of bulk materials. This technique of synthesis gives high M(s) of particles compared to other chemical routes.
Parekh
Kinnari
K
Department of Physics, Faculty of Sciences, The MS University of Baroda, Vadodara 390002, India.
Upadhyay
Ramesh V
RV
Aswal
Vinod K
VK