Title :
Preparation of magnetic nanoparticles (γ-Fe2O3) in the silica matrix
Author :
Niznansky, Daniel ; Rehspringer, Jean Luc ; Drillon, Marc
Author_Institution :
Inst. de Phys. et Chimie des Materiaux, Strasbourg, France
fDate :
3/1/1994 12:00:00 AM
Abstract :
Nanoparticles γ-Fe2O3 were prepared in silica matrix by the sol-gel process. Conventional acid hydrolysis and polycondensation of tetraethyl orthosilicate (TEOS) were used for the preparation of porous silica matrix. Iron(III) nitrate was homogeneously dissolved in the initial TEOS solution. After gelification and drying, the xerogel was heat treated on the air at different temperature between 700-900°C. The heating products were studied by high resolution TEM and magnetic measurements. Monocrystalline nanoparticles of γ-Fe 2O3 of size ranging between 50-100 Å were observed by HR TEM in the sample heated at 900°C. Room temperature magnetic measurements show a weak ferrimagnetic component for samples heated until 880°C, but a ferrimagnetic behaviour is evident at 4 K. The samples heated at higher temperature show ferrimagnetic behaviour at room temperature
Keywords :
ferrimagnetic properties of substances; heat treatment; iron compounds; magnetic properties of fine particles; particle size; porous materials; silicon compounds; sol-gel processing; transmission electron microscope examination of materials; γ-Fe2O3; 293 K; 700 to 900 C; 880 C; Fe2O3-SiO2; acid hydrolysis; drying; gelification; heat treatment; high resolution TEM; magnetic measurements; magnetic nanoparticles; polycondensation; porous silica matrix; room temperature; sol-gel process; tetraethyl orthosilicate; weak ferrimagnetic component; xerogel; Ceramics; Ferrimagnetic materials; Glass; Magnetization; Nanoparticles; Optical materials; Paramagnetic materials; Silicon compounds; Solids; Temperature;
Journal_Title :
Magnetics, IEEE Transactions on
