Preparation and Characterization of Ring-Shaped Co Nanomaterials
Preparation and Characterization of Ring-Shaped Co Nanomaterials
复制标题
环形钴纳米材料的制备及表征
DOI：
10.1021/cm7025784
复制
发表时间：
2008-07
影响因子：
8.6
通讯作者：
He, Lin
中科院分区：
文献类型：
--
作者：
Chen, Chinping;Liang, Fang;Guo, Lin;Meng, Xiangmin;Kong, Desheng;Wu, Ziyu;Wang, Ning;Wang, Siming;He, Lin
以PVP为表面改性剂，采用聚合物改性的方法成功地合成了甜甜圈或环状Co纳米材料。通过x射线衍射（XRD）、扫描电子显微镜（SEM）和透射电子显微镜（TEM）对合成产物进行了结构和形貌表征，通过温度和场相关磁化测量对合成产物进行了磁性表征。结果表明，这些环具有h-Co纳米结构。外径约400 ~ 500 nm，内径150 ~ 250 nm，环面厚度约120 nm。磁化测量表明，在300 K时，矫顽力约为112 Oe，在5 K时，矫顽力HC≈0几乎消失。利用面向对象微磁框架（OOMMF）封装的数值计算揭示了磁通闭合结构的磁化基态，与亚微米级Co环的几何结构一致。这就解释了观察到的为什么……
Donut- or ring-shaped Co nanomaterials were successfully synthesized using the polymer-modified method, by which PVP is used as a surface modifier reagent. The synthesized products were structurally and morphologically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), whereas the magnetic characterization was performed by temperature- and field-dependent magnetization measurements. The results show that the rings have a h-Co nanostructure. The outer diameter is about 400−500 nm, inner diameter 150−250 nm, and the ring plane thickness ∼120 nm. The magnetization measurements show a typical coercivity of about 112 Oe at 300 K and an almost vanishing coercivity, HC ≈ 0 at T = 5 K. Numerical calculations using the packeage of object oriented micromagnetic framework (OOMMF) reveal a magnetization ground-state of flux closure structure, as expected for the geometric structure of the submicrometer-sized Co rings. This explains the observed hy...