**1.6. Co-precipitation method**

This method is probably the most favorable to produce nanoparticles, as well as simple and very productive. A high homogeneity and uniformity can be easily obtained at moderate experimental conditions. In these last years, this kind of synthesis has been mainly used to produce nanoparticles with peculiar magnetic properties, in particular superparamagnetism for biomedical application. The particle growth is controlled only by kinetic factors, so by controlling pH, temperature, ionic strength, salts nature or the Fe(II)/Fe(III) concentration ratio, the shape and size of the nanoparticles can be customized [13].
