在室溫下同時具有鐵電與(反)鐵磁特性的多鐵性材料鉍鐵氧(BiFeO3,BFO)吸引了科學家們爭先投入了磁電交互作用的研究，可透過與鐵磁性導電材料結合以創造出可利用磁力或電力控制材料之磁電耦合交互作用之元件。
本實驗研究在室溫下具有鐵磁性的導電材料鑭鍶錳氧(La0.7Sr0.3MnO3)薄膜，希望使用脈衝式雷射沉積(PLD)技術，尋找在室溫下STO(001)與STO(111)兩基板上以不同氧氛壓(100mtorr、200mtorr、300mtorr、400mtorr)成長之具有最佳導電特性及鐵磁性質的薄膜，可用於後續研究多鐵性材料之底電極。
實驗結果顯示100mTorr樣品薄膜繞射峰位置相較其他高樣分壓樣品(200mTorr、300mTorr、400mTorr)有往小角度偏移的趨勢，而且電阻率也明顯高於其他樣品，不僅如此在低溫下量測磁滯曲線也發現有非單一鐵磁相情況產生，猜測是因為內部氧空缺較多，使錳氧錳之間較不易產生雙交換機制，造成結構、導電特性及磁特性的變化。而高氧氛壓下(200mTorr、300mTorr、400mTorr)成長之樣品皆具有較好的導電特性，及較高的居禮溫度Tc=350K，代表高氧氛壓下成長之樣品皆具有室溫鐵磁性及導電特性。而在高氧氛壓成長樣品中以在STO(111)基板上氧氛壓為200mTorr所成長之樣品，有極小的矯頑力代表此樣品錳離子之間交互作用較強烈，猜測此樣品氛壓適中使其內部磁疇(domain)排列方向較一致，不僅導電度佳且有較強的鐵磁特性。

Bismuth ferrite material (BiFeO3, BFO) exhibits ferroelectric and antiferromagnetic properties simultaneously at room temperature. It has attracted researchers to study the effect of magnetic and electric field controlled interaction between multiferroic/metallic ferromagnetic bilayer for room temperature device application.
In this work, we are investigating La0.7Sr0.3MnO3 thin films deposition on STO(001) and STO(111) substrate at different oxygen pressure (100mtorr、200mtorr、300mtorr、400mtorr) by Pulsed Laser Deposition technique, for using it as conducting layer in BPFO/LSMO/STO system in the future..
The results show 100mTorr thin film’s diffraction peak is shifted to lower degree than other higher oxygen pressure (200mTorr、300mTorr、400mTorr) thin films, the resistivity is higher than other sample, and the magnetization vs magnetic field measurement show that it has more than one ferromagnetic phases. It seems that this system have more oxygen vacancies than our other samples, which causes shift in diffraction peak, higher resistivity and imperfect phase (more than one ferromagnetic phases). Films deposited at higher oxygen pressure(200mTorr、300mTorr、400mTorr) are more conductive, have higher Curie Temperature (Tc=350K). These results show that thin films grown under higher oxygen pressure are better ferromagnetic conductor at room temperature. LSMO grown at STO(111) with 200mTorr oxygen pressure exhibits smallest thickness and smallest coercivity, which might be due to parallel domain alignment, that is why it has better conductive and magnetic properties.

論文審定書.............................................................................................................i
論文公開授權書......................................................................................................ii
誌謝..................................................................................................................... iii
摘要......................................................................................................................iv
Abstract.................................................................................................................v
目錄......................................................................................................................vi
圖目錄..................................................................................................................viii
第一章 前言............................................................................................................1
第二章 基本理論.....................................................................................................2
2-1 磁性物質的簡介[5][6]..........................................................................................2
2-2 順磁性(paramagnetic).........................................................................................2
2-3 鐵磁性(ferromagnetic).........................................................................................3
2-4 反鐵磁性(anti-ferromagnetic)...............................................................................4
2-5 亞鐵磁性(ferrimagnetic)......................................................................................5
2-6 抗磁性(diamagnetic)...........................................................................................5
2-7 Double-Exchange Model.....................................................................................6
2-8 Jahn-Teller distortion..........................................................................................8
2-9 La1-xSrxMnO3材料介紹.....................................................................................9
第三章 實驗方法及量測系統...................................................................................12
3-1 La0.7Sr0.3MnO3靶材製作.................................................................................12
3-2 SrTiO3基板清洗...............................................................................................14
3-3 La0.7Sr0.3MnO3薄膜成長.................................................................................15
3-4 脈衝式雷射沉積系統(PLD).................................................................................17
3-5 X光繞射儀(X-Ray Diffraction system).................................................................19
3-6 原子力顯微鏡(Atomic Force Microscopy,AFM)....................................................21
3-7 電性量測..........................................................................................................22
第四章 實驗結果與討論..........................................................................................26
4-1 La0.7Sr0.3MnO3靶材晶體結構...........................................................................26
4-2 La0.7Sr0.3MnO3薄膜晶體結構分析.....................................................................27
4-3 La0.7Sr0.3MnO3薄膜X光反射率(XRR)分析..........................................................30
4-4 La0.7Sr0.3MnO3薄膜表面形貌分析(AFM)............................................................32
4-5 La0.7Sr0.3MnO3薄膜電性分析...........................................................................34
4-6 La0.7Sr0.3MnO3薄膜磁性分析...........................................................................36
第五章 結論..........................................................................................................43
參考資料...............................................................................................................44

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