The Concept of a Low-Temperature Synthesis for Superparamagnetic BaFe12O19 Particles
Abstract:Superparamagnetic Ba-hexaferrite, BaFe12O19, nanoparticles were prepared by reacting tetrahydroxoferrates (III), [Fe(OH)4]−(aq), and barium ions, Ba2+(aq), in an autoclave in the presence of a high concentration of hydroxide ions OH−. The synthesis temperature was between 80° and 140°C. The size and the morphology of the synthesized nanoparticles were confirmed by transmission electron microscopy. The crystal structure of the nanoparticles was characterized by X-ray diffraction. The powders synthesized above 120°C exhibited a bimodal particle size distribution, while those synthesized below 120°C showed a monomodal particle size distribution. The field-cooled/zero-field-cooled magnetization measurements showed typical superparamagnetic behavior. The superparamagnetic nanoparticles synthesized below 100°C exhibited a disk-like shape, on average <10 nm wide and 3 nm thick, with a room-temperature magnetization of approximately 3 emu/g at 1 T.
Document Type: Research Article
Affiliations: 1: Faculty of Chemistry and Chemical Engineering, University of Maribor, 200 Maribor, Slovenia 2: Department for Materials Synthesis, Jožef Stefan Institute, 1000 Ljubljana, Slovenia 3: Kolektor Nanotesla Institute, 1000 Ljubljana, Slovenia 4: Institute of Mathematics, Physics and Mechanics, Faculty of Civil and Geodetic Engineering, University of Ljubljana, 1000 Ljubljana, Slovenia
Publication date: June 1, 2010