New electric double-layered magnetic fluids based on copper, nickel, and zinc ferrite nanostructures

We report on stable colloidal aqueous suspensions of magnetic nanostructures made of copper, nickel, and zinc ferrites. These magnetic fluids could represent a new alternative for biological applications. The basic steps of the nanoparticles synthesis, their chemical surface treatment, and their peptization in a stable colloidal sol are given. Their chemical composition is carefully checked, and X-ray diffraction patterns provide both their mean size and a structural characterization. Magnetization results obtained at 300 K are presented and discussed.