Formation And Properties Of Ferromagnetic/non-ferromagnetic Ni-zn, Co-Zn And Oxides Nanowires

Ferromagnetic/non-ferromagnetic binary alloy and oxide nanowires were electrodeposited in AAO template successfully. All the alloy nanowires were annealed at different temperature and the properities were studied. This dissertation is divided into three parts.1. In this work, perfect AAO templates were synthesized in different electrolytes, and the influences of components, concentration, pH value of the electrolytes and electrodeposition potential were discussed. Scanning electron microscope (SEM) and atom force microscope (AFM) were used to characterize the morphologies of the AAO template, respectively. The results show that the holes in the AAO templates synthesized in H2SO4 or C2H2O4 electrolyties are inerratic, while the channel in the AAO templates synthesized in H3PO4 divaricate easily. On the other hand, the hole diameter of the AAO template synthesized in H3PO4 is the maximum, and the one synthesized in H2SO4 electrolytie is the minimum.2. After that, NixZn1-x and CoxZn1-x binary nanowires were electrodeposited into AAO template at different eledtrodeposition potential, respectively. The structure, composition and morphologies of the synthesized samples were characterized by XRD, EDS, SEM and TEM. The XRD results of experiments showed that binary alloy nanowires can be synthesized by dc electrodeposition, and the structure of the nanowires changed with the composition, which can be changed by modulated the electrodeposition potential.The magnetic properties of the nanowire arrays were investigated using a PPMS-6000 superconducting quantum interference device magnetometer (SQUID). The results showed that there is a weaker magnetic anistropy for the nanowires fabricated at low potential, and which will be more obviously with the increasing electrodeposition potential. For the NixZn1-x samples, this phenomenon may due to the competition between the shape anistropy and magnetostatica coupling energy, while for the NixZn1-x samples, magnetic anistropy transition attribute to the competition between the shape anistropy and magnetocrystalline anistropy energy. 3. Co doped ZnO nanowires were systhesized successfully by post-annealed the CoZn alloy nanowires at 400℃, 500℃and 600℃in Ar/O2 mixed atmosphere, respectively. The structure and morphologies of the synthesized samples were characterized by XRD and TEM. Significant differences in the crystalline structures of samples annealed at different temperatures were observed. Magnetization measurements showed that the Co-doped ZnO nanowires exhibit room-temperature ferromagnetism and which changed with the annealing temperature, we attribute it to the re-distribution of Co atoms caused by the annealing course, which induced the change between Co2+ ions coupling.