本研究是在超高真空環境下將1 原子層的銀蒸鍍在銥(111)表面上，隨後再蒸鍍1~4原子層鈷上去，以歐傑電子能譜儀與表面磁光科爾效應儀對此超薄膜做表面組成及磁性的分析工作，並觀察銀中介層對鈷/銥系統所造成的磁性影響。對Co/Ir(111)系統而言，鈷薄膜厚度在1原子層時沒有磁滯現象，此時樣品為非鐵磁性，當鈷薄膜厚度為2原子層，在極向與縱向方向皆出現磁滯現象，樣品轉變為鐵磁性。銀中介層可有效壓制Co/Ir系統中氧雜質含量，然而銀原子在加熱後有往表面擴散的分凝現象，這是由於銀原子切割磁域結構，造成此薄膜系統的磁性熱穩定度下降。對x ML Co/1 ML Ag/Ir (111)而言，選定一系列Co薄厚度進行加熱退火處理，發現在適當溫度熱退火後，縱向磁滯消失而極向仍有磁滯現象，我們發現Co/Ag/Ir系統中具垂直異向性，以2 ML Co/1 ML Ag/Ir (111)為例，在不同退火溫度下，測量溫度為375 K，可以發現當退火溫度在500 K與650 K間有垂直異向性，此特性深具工業上高密度記憶媒體開發之應用潛力。 In this dissertation, surface composition and magnetic properties have been investigated for 0-4 monolayer (ML) Co/1 ML Ag/Ir(111) ultrathin films. As the Co thickness increase for a Co/Ir(111) system, no hysteresis was observed up to 2 monolayer (ML). hysteresis occurs on both the longitudinal and polar configurations and show ferromagnetism of the films. For x ML Co/1 ML Ag/Ir(111) films, a Ag buffer layer could efficiently suppress the natural oxygen contamination in the Co/Ir(111) system. Segregation of Ag atoms to the surface layers occurs after annealing treatments. This effect diminishes the thermal stability of the ferromagnetism. Systematic investigations show that perpendicular magnetic anisotropy (PMA) appears at a certain thickness and temperature range. As an example for 2 ML Co/1 ML Ag/Ir(111), the PMA temperature rang is between 500 and 600 K. These results show highly technological interest in high-density recording media development.
