Luminescent and Magnetic Properties of Fe 3 O 4 @SiO 2 @Y 2 O 3 :Eu 3+ Composites with Core–Shell Structure

Multifunctional Fe 3 O 4 @SiO 2 @Y 2 O 3:Eu 3+ composites were prepared with a facile solvothermal method followed by a subsequent heat treatment. Their structure and magnetic and luminescent properties were analyzed and discussed. Y 2 O 3:Eu 3+ phosphor as a shell was coated on the surface of Fe 3 O 4 @SiO 2 as the core to form Fe 3 O 4 @SiO 2 @Y 2 O 3:Eu 3+ composites. The particle size of the composites is 262.36 nm which consists of the magnetic core with about 210 nmin diameter and a silica shell with an average thickness of about 20 nm. It exhibits ferromagnetic behavior with the special saturation magnetization M s of 12.62 emu/g, the negligible coercivity H c, and remanence M r at room temperature and exhibits a strong red emission peak originating from the electric–dipole transition 5 D 0 → 7 F 2 of Eu 3+ ions at 611 nm. The current and potential biomedical uses include biological imaging, cell tracking, and magnetic bioseparation.