鐵／銀多層超薄膜磁性研究

由先前實驗已知在1.2原子層(ML) Fe/Pt(111)上逐漸覆蓋1.4 ML的銀時，其磁化易軸從平行表面方向轉變為垂直表面方向，當鐵覆蓋厚度達到l ML時；同時垂直方向的磁化強度與矯頑力兩者皆達到最大值。現以1.4 ML Ag/1.5 ML Fe/Pt(111)為基底材料，再蒸鍍上不同原子層數的鐵薄膜，使用磁光柯爾效應儀(MOKE)探測Fe超薄膜覆蓋於1.4 ML Ag/1.5 ML Fe/Pt(111)樣品前後之表面磁性變化，並藉由歐傑電子能譜術(AES)鑑別樣品表面組成成分、計算薄膜厚度，以及低能量繞射電子儀(LEED)研究表面結構，結果發現其垂直方向的磁化強度與矯頑力皆與最上層鐵覆蓋的增加而減少而消失，磁化易軸從垂直面方向完全轉至平行面方向，即所謂發生電子自旋指向轉變(SRT)現象。由於平行面方向飽和磁化隨鐵磁層厚度增加而相對應增加，反應出此系統中由銀仲介層所隔閡開的兩鐵原子層為磁矩順向排列。

關鍵字

磁性薄膜；柯爾效應；鐵；銀；歐傑電子

並列摘要

The spin-reorientation transition(SRT) is observed when Ag overlayers deposited on Fe/Pt(111) by magneto-optical Kerr effect measurements. The polar Kerr intensity and its coercivity as a function of Ag coverage are investigated through SRT. The easy axis of the magnetization changes completely from the in-plane to out-of-plane direction after l ML of Ag coverage. Both the polar Kerr intensity and perpendicular coercivity have thrir maximal value at d(subscript Ag)=1 ML. The hybridization of electron states at the Ag/Fe interface causing the change in interface magnetic anisotropy may be the mechanisms of the spin-reorientation transition induced by Ag.