多鐵性材料是個磁電耦合材料，可以利用改變電場來控制材料中的電偶極矩，而利用電偶極矩去影響鄰近層的磁矩方向，相反的，亦可利用磁矩來影響電偶極矩。至今為止，BiFeO3鐵酸鉍是最重要同時鐵電性轉變溫度(TC≒1103K)與反鐵磁性轉變溫度(TN≒643K) 皆在室溫的以上的多鐵性材料。然因BiFeO3的準正方結構，具有八個近乎簡併的電偶極矩，導致以往延[100]方向成長之薄膜面對極為複雜的偏極化取向。再加上電疇邊界漏電的缺陷而無法順利應用。本研究擬採用延[111]方向成長薄膜來簡化偏極化取向，以及使用摻鉛Pb的BiFeO3來克服電疇邊界漏電的問題。實驗上則利用脈衝雷射濺鍍法，在原子級平整SrTiO3(111)基板上成長出高品質SrRuO3與摻鉛Pb的BiFeO3雙層薄膜，借由壓電反應顯微鏡(piezoresponse microscope) 來研究上述的問題。實驗結果證實我們的想法完全正確。

Multiferroics is a material involving multiple couplings between electricity, magnetism and strain and, therefore, has great potential for applications, such as memory devices. Especially for magnetoelectric multiferroics which possesses inherent coupling between magnetic and ferroelectric order parameters that could be used as an indirect mechanism to switch magnetic moment of adjacent magnetic layer by changing the polarity of the electric field and vice-versa. Up to date, BiFeO3 is the best candidate for it exhibits ferroelectric (TC≒1103K) and antiferromagnetic ordering temperature (TN≒643K) above room temperature. However, due to the pseudocubic structure of BiFeO3 crystal, eight degenerate electric polarization along diagonal directions that are very difficult to control, and the electric leakage at domain walls challenge the application technique. In our research, we trys to overcome these obstacles by growing BiFeO3 films along [111] direction and use Pb-doped BiFeO3 to stop the electric leakage. The Pb-doped BiFeO3 film were grwon on atomically flat SrTiO3 (111) substrates by a pulse laser ablation technique. The electric polarization of Pb-doped BFO was observed by a piezoresponse microcope. In this project, we success in overcome all these difficulties and accomplish the goal to switch the electric polarization of the system along out-of-plane direction.

論文審定書 i
誌 謝 ii
摘 要 iii
Abstract iv
目 錄 v
圖 次 vii
第一章 前言 1
第二章 基本理論介紹 2
2-1 磁性物質的簡介 2
2-1-1 順磁性(Paramagnetic) 3
2-1-2 反磁性(Diamagnetic) 4
2-1-3 鐵磁性(Ferromagnetic) 5
2-1-4 亞鐵磁性(Ferrimagnetic) 7
2-1-5 反鐵磁性(Anti-ferromagnetic) 8
2-2 介電極化特性 9
2-3 SrRuO3材料特性 11
2-4 BiFeO3鐵酸鉍材料特性 14
第三章 實驗方法、量測系統 22
3-1 SrTiO3(111)基板清洗 22
3-2 Bi0.9Pb0.1FeO3/SrRuO3薄膜成長 24
3-3 脈衝式雷射鍍膜系統(Pulsed Laser Deposition) 26
3-4 光學微影製程 28
3-5 X光繞射儀(X-Ray Diffraction system) 30
3-6 穿透式電子顯微鏡(Transmission Electron Microscope) 31
3-7 原子力顯微鏡(Atomic Force Microscopy, AFM) 32
3-8 電性量測 33
第四章 實驗結果與討論 34
4-1 SrTiO3(111)基板酸蝕處理比較 34
4-2 SrRuO3薄膜表面形貌分析(AFM) 38
4-3 Bi0.9Pb0.1FeO3薄膜表面形貌分析(AFM) 43
4-4 漏電流量測 45
4-5 壓電力顯微術量測 48
4-6 穿透式電子顯微鏡量測 56
第五章 結論 60
參考資料 61

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