Preparation and properties of magnetic Fe3O4 hollow spheres based magnetic-fluorescent nanoparticles

• A new material which the hollow structured Fe3O4@Gd2O3:Eu3+ nanoparticles were synthesized.
• The hollow particles exhibited the luminescence intensity 2.45 times than the solid samples.
• The saturation magnetization of hollow particles is higher than the solid sphere samples.
• The mechanism for this enhancement was clarified and addressed.
• The properties of the particles are acceptable for biomedical applications.

In this paper, magnetic Fe3O4 hollow spheres based magnetic-fluorescent nanoparticles, hollow structured Fe3O4@Gd2O3:Eu3+, were synthesized through a homogeneous precipitation method. The microstructure, luminescence, and magnetic properties of the samples were investigated and discussed with the help of various analytic techniques including X-ray diffraction, scanning electron microscope, energy dispersive spectrometer, cathodelumincence mapping, photoluminescence spectra and vibrating sample magnetometer. The hollow spheres nanoparticles, emitting at 612 nm dominantly under the 254 nm excitation, exhibited the photoluminescence intensity 2.45 times higher than the solid sphere samples, due to the. hollow spheres structure. The hollow Fe3O4@Gd2O3:Eu3+ nanoparticles were spherical, and had a particle size of about 1400 nm in diameter. They also showed a saturation magnetization of 1.33 emu/g, a coercivity Hc of 160 Oe and a remanence of 0.05 emu/g at room temperature, the saturation magnetization of hollow spheres nanoparticles is higher than the solid sphere samples. The enhanced photoluminescence and magnetic properties of the hollow structured nanoparticles allow them to be used in biomedical applications.