ABSTRACT: Yttrium aluminum iron garnet Y3Fe5−xAlxO12 compounds were produced by the citrate gel process by varying the aluminum content x from 0 to 2. Particles with an average size of about 100 nm and a specific surface area ranging from 6 to 28 m2/g were obtained. Curie temperatures (TC) were determined from the temperature dependence of the field-cooled magnetization (FCM) and the remnant magnetization (REM) and range from –40°C to 280°C. According to the magnetic moment variation, the aluminum cation seems to replace the iron cation in the tetrahedral site for compounds with x<0.7. 3-Aminopropyltrimethoxysilane (γ-APS) was grafted onto the particles surface and its presence confirmed by infra-red spectroscopy. Cytotoxicity assays were carried out during a period of 13 days using human microglia and rat glioblastoma cell lines. The presence of the amine-functionalized particles did not affect the cell viability or the culture growth rate. Finally, amine-functionalized particles were successfully labeled with covalently linked fluorescing molecules.
Journal of Magnetism and Magnetic Materials.