Synthesis and Characterization of Magnetic Nanowires
Date Issued
2007
Date
2007
Author(s)
Hsin, Chia-Fen
DOI
zh-TW
Abstract
In first part of thesis, we successfully demonstrated synthesis of Co-Pt alloy nanowire via electrochemical deposition in porous alumina templates. The Co-Pt alloy nanowires were converted from chemical disorder structure to CoPt3 (L12) through reduction process followed by alloy formation at high temperature. The elemental analysis and crystal structure analysis were carried out using energy-dispersive and X-ray diffraction method, respectively. The chemical order structure of CoPt3 nanowires was formed above annealing temperature of 500˚C. X-ray absorption spectroscopy revealed valuable information about the electronic structure and local structures at each stage. According to above results, we propose an annealing mechanism for the transformation process of CoPt nanowires.
In second part, we demonstrate a simple method to tune the optical properties of thin films of nickel nanowires grown inside an anodic alumina oxide (AAO) template by manipulating anodizing conditions. The optical properties of the metal plate can be effectively tuned by adjusting the thickness of porous alumina oxide. Under the present experimental conditions, we found that the thickness of the porous alumina oxide depends strongly on the current density because the duration of anodization was maintained constant. The transmission electron microscopic image of the cross section reveals the growth of nickel nanowires which were embedded in porous alumina oxide. Due to the interference between incident light and reflected light, the anodic alumina oxide plate exhibits a variety of color. This demonstration of tuning of optical behavior makes its usefulness in technological application possible by scaling up of the preparation of metal/oxide nanostructures exhibiting color tuning in the visible region.
Subjects
磁性奈米線
鈷鉑合金
X光吸收光譜
Magnetic nanowires
CoPt alloy
X-ray absorption spectroscopy
Type
thesis
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