Cryochemical Synthesis of Magnetic Nanoparticles

Magnetic nanoparticles of maghemite (γ-Fe2O3), cobalt (CoFe2O4), and zinc ferrites (ZnFe2O4) with varied size and morphology were synthesized by means cryochemical technologies. The synthesis route involved cryogenic spray drying of organic metal salts followed by their subsequent thermal decomposition. The use of iron(II) gluconate and iron(III) ammonium citrate as precursors results in the formation of micron-sized maghemite macroporous particles and 50–150 nm nanoparticles aggregated into micron-sized plate-shaped structures, respectively. Both maghemite samples exhibited an admixture of goethite. If solutions of iron acetylacetonate with zinc or cobalt acetate are used as precursors, then ZnFe2O4 nanoparticles with average size 10 nm and CoFe2O4 nanoparticles with average size 15 nm are formed.