| Summary: | 碩士 === 國立中央大學 === 化學工程與材料工程研究所 === 97 === In this study, the AAO template with large-area nanopores structure and the large-scale well-aligned pure Ni, Co, and Co-Ni alloy nanowires arrays with different composition ratio of Co and Ni were successfully fabricated under controlled processing conditions. The average pore size of the AAO template produced was about 25 nm. On the other hand, pure Ni, Co, and Co-Ni alloy nanowires with different concentration ratios of Co to Ni (Co:Ni=1:9, Co:Ni=1:1, Co:Ni=9:1) were successfully synthesized by DC electrodeposition into nanopores of commercial AAO template. Based on the TEM and SAED analyses, it is found that the Ni and Co nanowires were polycrystalline with FCC and HCP structures, respectively. In addition, the three sets of Co-Ni alloy nanowires were all single crystalline, and these single crystalline Co-Ni nanowire possess a HCP structure. The average diameter of the metal and alloy nanowires was about 250 nm. From the EDS line-scan profiles analysis, it is revealed that alloy nanowires were entirely composed of Co and Ni, and uniform distributions of Co and Ni throughout these nanowires. The growth direction of the Co-Ni alloy nanowires of samples A (Co:Ni=1:9), B (Co:Ni=1:1), and C (Co:Ni=9:1) were identified to be along the[-6241], [-3211], and [02-21] directions, respectively.
From electrical property measurement, the addition of Co to Ni could strongly affect the resistivity of Co-Ni alloy nanowires. The resistivity of Co-Ni nanowire was found to increase with the addition of Co to Ni first then decrease. The results are discussed in the context of the Nordheim’s rule. On the other hand, the Co-Ni nanowires were found to be very sensitive to the externally applied magnetic field. In this study, experimental result demonstrated that by applying external magnetic fields, these Co-Ni nanowires can be controlled to align along the directions of applied magnetic filed and assemble into a 2D ordered pattern on Si substrate.
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