In this paper we outline different ways to make magnetic fluids from colloidal selfassemblies (normal and reverse micelles) and describe the preparation of both ferrite nanocrystals with various compositions and cobalt metal nanocrystals. The general magnetic behaviors are described but it is found that these are not applicable to the whole variety of ferrites produced. Ferrite and cobalt magnetic fluids are organized in 3D superlattices to form various mesoscopic structures. Within a number of limitations, the magnetic properties of both the above nanocrystals and these fluids have been determined and described.
Source : Ferrite Magnetic Fluids: A New Fabrication Method and Magnetic Properties of Nanocrystals differing by their size and composition. M.P. Pileni Advanced Functionalized Material, 2001, 11 , 323- 336.