Saiyasombat C, Petchsang N, Tang I M, Hodak J H
Department of Physics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
Nanotechnology. 2008 Feb 27;19(8):085705. doi: 10.1088/0957-4484/19/8/085705. Epub 2008 Feb 4.
A one-pot aqueous chemical synthesis for silica-passivated ferromagnetic nanoparticles is presented. The average size of these particles is 84 ± 20 nm. The x-ray and electron diffraction experiments revealed that the nanoparticles are mainly composed of polycrystalline iron boride. The broad x-ray diffraction peak leads to an average crystallite size of 1.8 nm, which is much smaller than the overall size of the particles, and is consistent with the polycrystalline nature of the samples. Mössbauer spectroscopy and magnetization experiments were used to establish the room temperature magnetic properties as well as the chemical nature of the particles. Fe(2)B dominates the composition of the nanoparticles, having a hyperfine field broadly distributed in the 10-33 T range. Alpha iron, the second ferromagnetic material identified in the particles, amounts to 4.6% of the composition. Finally, a paramagnetic phase accounting for approximately 14.6% of the material of the particles was also detected. These nanoparticles contain a core with soft ferromagnetic properties surrounded by a passivating silica layer, and are suitable for magnetically targeted drug delivery and electromagnetic induction heating applications.
本文介绍了一种用于二氧化硅钝化铁磁纳米粒子的一锅水相化学合成方法。这些粒子的平均尺寸为84±20纳米。X射线和电子衍射实验表明，纳米粒子主要由多晶硼化铁组成。宽的X射线衍射峰导致平均微晶尺寸为1.8纳米，这远小于粒子的整体尺寸，并且与样品的多晶性质一致。穆斯堡尔光谱和磁化实验用于确定室温磁性能以及粒子的化学性质。Fe(2)B在纳米粒子的组成中占主导地位，其超精细场在10 - 33特斯拉范围内广泛分布。α铁是在粒子中鉴定出的第二种铁磁材料，占组成的4.6%。最后，还检测到一个顺磁相，约占粒子材料的14.6%。这些纳米粒子包含一个具有软铁磁性质的核心，周围是钝化二氧化硅层，适用于磁靶向药物递送和电磁感应加热应用。
