通过尿素均匀沉淀法合成了荧光磁性Fe₃O₄@Gd₂O₃∶Eu³⁺纳米空心球，并且设计了一种壳-壳结构。利用模板法合成的这种壳-壳结构很好地避免了磁性纳米粒子的凝聚。扫描电子显微镜(SEM)和透射电子显微镜(TEM)测试结果表明，得到的Fe₃O₄@Gd₂O₃∶Eu³⁺空心球直径均约为390 nm，并且磁性层和荧光层的厚度分别约55 nm 和15 nm。壳的厚度和空心纳米球的尺寸可以很容易地通过调整原料的浓度和氧化硅模板的尺寸来控制。所制备的Fe₃O₄@Gd₂O₃∶Eu³⁺空心球表现出较高的饱和磁化强度(17.1 emu/g)，在紫外线的激发下发出较强的红光。这种特征使它完全可以应用于靶向治疗、免疫检测、磁性分离、荧光追踪等方面。该合成路线对其他多功能纳米空心球的可控合成也具有重要的意义。

Multifunctional Fe₃O₄@Gd₂O₃∶Eu³⁺ hollow nanospheres are prepared via a urea-based homogeneous precipitation method. The multifunctional layers are designed to a shell- shell structure to avoid the magnetic nanoparticles clustering. Scanning electron microscope (SEM) and transmission electron microscope (TEM) images indicate that the as-obtained Fe₃O₄@Gd₂O₃∶Eu³⁺ sample consists of uniform nanospheres with an average diameter of 390 nm, and the thicknesses of magnetic and fluorescent layers are about 55 nm and 15 nm, respectively. The shell thickness and the size of the hollow nanospheres can easily be controlled via adjusting the concentration of raw materials and the size of silica template. The sample of Fe₃O₄@Gd₂O₃∶Eu³⁺ shows high saturation magnetization of 17.1 emu/g and strong red emission under ultraviolet excitation, which may be applied in targeted therapy, immune detection, magnetic separation, luminescence detection and so on. This synthesis route is of great significance in the controllable synthesis of other multifunctional hollow nanospheres as well.