Preparation and Characterization of Ring-Shaped Co Nanomaterials

被引：29

作者：

Guo, Lin ^{[1
]}

Liang, Fang ^{[1
]}

Wang, Ning ^{[1
]}

Kong, Desheng ^{[2
]}

Wang, Siming ^{[2
]}

He, Lin ^{[2
]}

Chen, Chinping ^{[2
]}

Meng, Xiangmin ^{[3
,4
]}

Wu, Ziyu ^{[5
]}

机构：

[1] Beijing Univ Aeronaut & Astronaut, Sch Chem & Environm, Beijing 100083, Peoples R China

[2] Peking Univ, Dept Phys, Beijing 100871, Peoples R China

[3] Chinese Acad Sci, Lab Optoelect Funct Mat & Mol Engn, Beijing 100080, Peoples R China

[4] Chinese Acad Sci, Tech Inst Phys & Chem, Beijing 100080, Peoples R China

[5] Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China

来源：

CHEMISTRY OF MATERIALS | 2008年 / 20卷 / 16期

基金：

中国国家自然科学基金;

关键词：

D O I：

10.1021/cm7025784

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

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 similar to 120 nm. The magnetization measurements show a typical coercivity of about 112 Oe at 300 K and an almost vanishing coercivity, H-C approximate to 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 hysteresis loops at low temperature with a vanishing small coercivity. A possible reaction process for the formation of the donut-shaped Co nanostructure is presented.

引用

页码：5163 / 5168

页数：6

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