Synthesis of high coercivity cobalt nanotubes with acetate precursors and elucidation of the mechanism of growth
Synthesis of high coercivity cobalt nanotubes with acetate precursors and elucidation of the mechanism of growth
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DOI：
10.1021/jp8035007
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发表时间：
2008-09-18
影响因子：
3.7
通讯作者：
Anantharaman, M. R.
中科院分区：
文献类型：
--
作者：
Narayanan, T. N.;Shaijumon, M. M.;Anantharaman, M. R.
首次采用阳极氧化铝模板电沉积醋酸钴的方法制备了具有很高纵向电导率的钴纳米管。用X射线衍射（XRD）、场发射扫描电子显微镜（FESEM）和透射电子显微镜（TEM）对样品进行了表征。观察到高度有序的六方钴相的形成。室温超导量子干涉仪（SQUID）磁强计测量表明，磁化的易磁化轴平行于纳米管轴。这些CoNTs表现出非常高的纵向磁化率类似于820 Oe。一个非常高的管间的相互作用所造成的静磁偶极纳米管之间的相互作用被观察到。厚壁纳米管也通过使用乙酸钴四水合物前体制造。提出了一种基于迁移率辅助生长的CoNTs形成的合理机制。水化层的作用和金属离子的流动性的情况下，一维几何形状的生长机制阐明。
Cobalt nanotubes (CoNTs) with very high longitudinal coercivity were prepared by electrodeposition of cobalt acetate for the first time by using anodized alumina (AAO) template. They were then characterized with X-ray diffraction (XRD), a field emission scanning electron microscope (FESEM), and a transmission electron microscope (TEM). Formation of a highly ordered hexagonal cobalt phase is observed. Room temperature SQUID (superconducting quantum interference device) magnetometer measurements indicate that the easy axis of magnetization is parallel to the nanotube axis. These CoNTs exhibit very high longitudinal coercivity of similar to 820 Oe. A very high intertubular interaction resulting from magnetostatic dipolar interaction between nanotubes is observed. Thick-walled nanotubes were also fabricated by using cobalt acetate tetrahydrate precursors. A plausible mechanism for the formation of CoNTs based on mobility assisted growth is proposed. The role of the hydration layer and the mobility of metal ions are elucidated in the case of the growth mechanism of one-dimensional geometry.