從之前的研究告訴我們，理論計算上， Co/Au(111) 系統的Spin Reorientation
Transition (SRT) 厚度在1.0973 nm ，大約是5 ML 附近。本次的實驗中，利用
PEEM (Photo Emission Electron Microscopy) 、SMOKE (Surface Magneto-optic
Kerr Effect) 的檢測，得到Co/Au(111) 磁區一連串連續變化之圖形，我們得知
了SRT 的厚度大概在4.5 - 5.5 ML ，恰好涵蓋在理論計算之SRT 範圍內，而從
SMOKE 我們觀察到，在SMOKE 的in-plane 與out-of-plane 方向之測量，可以
看到out-of-plane 的部分在低層數時有磁滯曲線的存在，並隨著鈷的厚度增加而
減小，一直到6.8-7.3 ML 的範圍內，in-plane 與out-of-plane 的磁滯曲線共存，
in-plane 的曲線開始變大，直到過了7.3 ML 則out-of-plane 磁滯曲線完全消失，
這表示磁性是由out-of-plane 轉變至in-plane 的過程，磁區電子自旋的方向則是
從指向垂直表面(out-of-plane) ，轉變為指向平行表面(in-plane) ， PEEM 的厚
度結果與MOKE 不同，我們推論可能是因為樣品移動距離較長，所導致的累積誤
差所造成，或是因為我們採用斜面樣品的形式，所以樣品形貌影響到了MOKE 的
量測。另外， SMOKE 在SRT 區塊的表現，出現了蜂腰形式的磁滯曲線圖形，這
代表了電子自旋指向中的垂直表面與平行表面之分量在競爭，因而皆表現出來並
且疊加，產生如此圖形。

為了解決未來在PEEM 檢測中外加磁場的問題，我們做了一項嘗試，將鐵額外
鍍在Co/Au(111) 系統，並在中間利用金的厚度調控其影響力，藉以觀察此鐵磁
性物質與原系統間的交互作用。從此測試得知Co 與Fe 鍍膜磁區會鐵磁性耦合，
且金在此測試中影響不大，可能是因為金的厚度鍍得不夠厚，造成金斜面層調控
鐵層影響鈷的效應不明顯。

From previous research for theoretical calculation of Spin Reorientation Transition
(SRT) on Co/Au(111) system, we know the SRT thickness is at 1.0973 nm,
which is approximately 5 ML. In this experiment, using photo emission electron
microscopy (PEEM) and surface magneto-optic Kerr effect (SMOKE), the image
of magnetic domain evolution of Co/Au(111) system is mapped out, and the
SRT region at 4.5 - 5.5 ML is determined. The result corresponds the theoretic
calculation result.
By SMOKE, we found that at lower thickness of Co, the out-of-plane hysteresis
loop exists. The out-of-plane loop is shrinking with increase of Co thickness.
At 6.8-7.3 ML Co, the out-of-plane and in-plane hysteresis loops co-exist. And
the in-plane loop becomes larger with increase of Co thickness. After exceeds
7.3 ML Co layer, the out-of-plane loop disappears. With this result, we know that
the spin reorientation is from out-of-plane to in-plane. And the reason which the
thickness is not match PEEM data, is inferred by accumulation error by moving
the sample in long range, or the impact from geometry of sample in MOKE
measuring.
Also, the wasp-waisted hysteresis loops in MOKE are discovered during SRT
region, which means that the competition of components between out-of-plane
and in-plane appear, and both of the loops are overlapped.
On the other hands, in order to solve the problem for adding external magnetic
field when doing PEEM measurement, we gave a trial. We deposited another
ferromagnetic material on Co/Au(111) system, which is Fe, and tried to use controlling
Au thickness between Co and Fe layer to adjust the effect from Fe layer.
The objective is to see the interaction between Fe and original system. From this
test, it’s been observed that domains on Co and Fe are ferromagnetic coupling,
and Au didn’t contribute for adjusting the Fe influence. This phenomenon may
be caused by the lack of thickness of Au layer or the shift of SRT region with
ferromagnetic coupling.

論文審定書 i
誌謝 iii
中文摘要 iv
英文摘要 v
1 研究背景與問題申明 1
1.1 關於磁區研究之背景. . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 實驗動機與問題申明. . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2.1 實驗動機. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2.2 問題申明. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 磁區特性觀測之文獻回顧. . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3.1 Spin Reorientation Transition (SRT) 相關之結果. . . . . . . 2
1.3.2 對於尋找Skyrmion 的價值. . . . . . . . . . . . . . . . . . . 3
1.4 實驗目標. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.5 實驗步驟. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 實驗原理及性質 9
2.1 薄膜成長的性質. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1.1 晶格不匹配(Lattice Mismatch) . . . . . . . . . . . . . . . . . 9
2.1.2 斜面的成長. . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2 關於材料磁能之原理. . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2.1 磁性的作用種類. . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 磁轉向行為(Spin Reorientation Transition, SRT) 之成因與性質. . . 14
2.3.1 磁區的形成與磁能之交互作用. . . . . . . . . . . . . . . . . . 14
2.3.2 磁區寬度隨薄膜厚度之變化. . . . . . . . . . . . . . . . . . . 15
2.3.3 磁各向異性(Magnetic Anisotropy) . . . . . . . . . . . . . . . 16
3 實驗儀器及原理 19
3.1 材料成長儀器的介紹. . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.1.1 電子束蒸鍍槍(Electron Beam Evaporator) . . . . . . . . . . 19
3.2 薄膜成長測量的相關儀器. . . . . . . . . . . . . . . . . . . . . . . . . 19
3.2.1 Auger Electron Spectroscopy (AES) . . . . . . . . . . . . . . 19
3.2.2 Medium Energy Electron Diffraction Spectroscopy (MEED) 20
3.3 薄膜磁性測量的相關儀器. . . . . . . . . . . . . . . . . . . . . . . . . 23
3.3.1 Surface Magneto-Optic Kerr Effect (SMOKE) . . . . . . . . . 23
3.3.2 X-ray Magnetic Circular Dichroism Spectroscopy (XMCD) . 23
3.3.3 Photoemission Electron Microscopy (PEEM) . . . . . . . . . 26
4 結果與討論 31
4.1 Fe/Au steps/Co wedge/Au(111) 樣品上的薄膜與座標設置. . . . . 31
4.2 從MEED 測量數據校正薄膜之成長鍍率. . . . . . . . . . . . . . . . 32
4.3 以AES 測量數據進行之校正. . . . . . . . . . . . . . . . . . . . . . . 39
4.3.1 AES 對於薄膜均勻度之校正. . . . . . . . . . . . . . . . . . . 39
4.3.2 AES 對鈷厚度隨訊號比值變化之標定. . . . . . . . . . . . . . 43
4.4 SMOKE 測量之結果. . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.4.1 Spin Reorientation Transition Result By MOKE . . . . . . . 46
4.5 XMCD-PEEM 量測下的磁區演變. . . . . . . . . . . . . . . . . . . . 49
4.5.1 鈷薄膜磁區外觀及寬度的改變. . . . . . . . . . . . . . . . . . 49
4.5.2 Co/Au 在SRT 區域內的磁各向異性( Anisotropy ) . . . . . . 53
4.5.3 鐵薄膜隨金臺階變化對於鈷SRT 區域的影響. . . . . . . . . 53
5 結論與總結 61
參考文獻 63

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