Anodic Alumina Template Pore-forming Mechanism Of The Fept Magnetic Nanowire Array Synthesis

Nano-materials have attracted more and more attentions recently due to the unique physical and chemical properties. In the further research, nano-materials show great future of potential applications in catalyst, filtrating light, light absorption, medicine, and magnetism storage media. Now the attention has changed from the property exploration of single nano-structure material to the fabrication of nano-structure with special property. Template-assisted electrochemical method (TAE) is an important way in production of nano-materials. The structure of nano-material is directly controlled by the inner structure of the template. Nanowires, nanotubes and nanodots are achievable easily through TAE. Anodic aluminum oxide (AAO) template is widely used in TAE because of its uniform pore-size distribution and stable chemical properties.In this paper, we discussed some problems we met in the fabrication of FePt nanowire arrays in AAO template, including the improvement of AAO template and the electrodeposition process.In the improvement of templates, we systematically studied the whole process of electropolished and two anodizations, through examining the surface changes of the formed alumina film by means ofFE-SEM. We found the electropolished process can produce a nano-stucture, and the pore distance is proportionate to the applied voltage. Based on the improved electropolished process, we successfully made AAO template with a small pore distance at low anodized voltage.In the aspect of electrochemical deposition, we produced the FePt nanowire arrays of an atomic ratio 1:1 with PED method. In order to explain the morphology, composition, and magnetic properties, we proposed a new growth model of two electrodes system. Instead of the deposition of Fe and Pt was synchronous, we regarded Pt would be reduced firstly. The inhibition effect will be weakened when the concentration of [PtCl6]2- and [PtCl4]2- ions decreases to a certain level. This new growth model can help us to understand the low coercivity of FePt nanowire arrays and the alternating light and dark distribution in some nanowires.