| Summary: | 碩士 === 國立中正大學 === 物理所 === 96 === Abstract
In this dissertation, effects of silicon capping layers on the physical properties for ultrathin Co/Ir(111) films have been investigated using Auger electron spectroscopy, sputtering depth profiling, low-energy electron diffraction, and surface magneto-optic Kerr effect (SMOKE) techniques. As Si atoms are deposited on Co/Ir(111), the interaction of Si atoms with Co films results in the occurrence of defects which impede the moving of domain walls and the coercivity increases. As the thickness of the Si layer increases, both the reduction of ferromagnetic layers and the superparamagnetic behavior diminish the remanence Kerr intensities. A magnetic phase diagram for the Si-Co binary system on Ir(111) has been established. Structural analysis shows that the full width at half maximum of the diffraction spots increases as the Si atoms deposited on Co/Ir(111). Meanwhile the intensity of the diffraction spot decreases to zero for few-tenth monolayer of Si deposit. This shows that the silicides do not exhibit a long-range order. After annealing treatments, the kinetic energy of Si Auger signal decreases because of the formation of Co silicides. At higher temperatures, Co starts to diffuse into the iridium substrate and this effect results in the increase of the kinetic energy of Si Auger signal. From the SMOKE measurements, the films are nonferromagnetic at high temperatures.
Keywords:
surface magneto-optic Kerr effect, Auger electron spectroscopy, sputtering depth profiling, low-energy electron diffraction, silicon, silicide, cobalt, magnetic phase diagram.
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