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.
Department of Physics, Faculty of Sciences, The MS University of Baroda, Vadodara 390002, India.
Kinnari
K
Parekh
Ramesh V
RV
Upadhyay
Vinod K
VK
Aswal