Department of Applied Chemistry, Faculty of Engineering, Tokyo University of Science Yamaguchi, Yamaguchi, Japan.
Nanotechnology. 2010 Mar 5;21(9):095603. doi: 10.1088/0957-4484/21/9/095603. Epub 2010 Jan 29.
We first succeeded in preparing ferromagnetic materials of SmCo(5) nanoparticles in sizes of single nanometers by a chemical route using a polyol process. In order to produce ferromagnetic SmCo(5) nanoparticles with a CaCu(5)-type structure, the chemical preparation was conducted under a molar ratio of 1:1.3 of Sm:Co as compositions of metallic precursors when tetraethylene glycol (TEG), and oleic acid and oleylamine were used as a reductant and protectant, respectively. However, XRD profiles of the products showed the presence of oxides and other by-products besides the CaCu(5)-type structured nanoparticles. The best metallic precursors and protective reagent to prevent oxidization under reaction were SmCl(3) and Co(acac)(3), and 1-adamantanecarboxylic acid (ACA) and poly(N-vinyl-2-pyrrolidone) (PVP), respectively when TEG was used as the reducing reagent. We found that oxides and other by-products were not detected and pure SmCo(5) nanoparticles with the CaCu(5)-type structure were prepared under the chemical condition. The SmCo(5) nanoparticles coated by ACA and PVP were 6.2 nm in diameter and showed a coercivity of 1500 Oe at 300 K.
我们首次通过化学途径，使用多元醇工艺，成功制备了 SmCo(5)纳米颗粒的铁磁材料，其尺寸为单纳米级。为了制备具有 CaCu(5)型结构的铁磁 SmCo(5)纳米颗粒，化学制备在 Sm:Co 的摩尔比为 1:1.3 的条件下进行，作为金属前体的组成部分，当使用四乙二醇（TEG）、油酸和油胺分别作为还原剂和保护剂时。然而，产物的 XRD 图谱显示除了 CaCu(5)型结构纳米颗粒之外，还存在氧化物和其他副产物。当 TEG 用作还原剂时，最佳的金属前体和防止反应中氧化的保护试剂分别是 SmCl(3)和 Co(acac)(3)，以及 1-金刚烷羧酸（ACA）和聚（N-乙烯基-2-吡咯烷酮）（PVP）。我们发现，在化学条件下，没有检测到氧化物和其他副产物，并且制备了具有 CaCu(5)型结构的纯 SmCo(5)纳米颗粒。由 ACA 和 PVP 包覆的 SmCo(5)纳米颗粒的直径为 6.2nm，在 300K 时的矫顽力为 1500Oe。
