龐磁阻(Colossal Magnetoresistance)薄膜成長於晶格不匹配的基板時，會因薄膜/基板介面應力的影響，進而改變薄膜之磁性及電性轉換。La0.7Ca0.3MnO3(LCMO)及 La0.7Sa0.3MnO3(LSMO)薄膜不論在伸張或收縮應力的影響下，轉換溫度均呈下降趨勢，唯獨La0.8Ba0.2MnO3(LBMO)薄膜呈現不同的趨勢，其轉換溫度或上升或下降。當吾人使用射頻磁控濺鍍系統以離軸方式成長La0.8Ba0.2MnO3(LBMO)/SrTiO3(STO)薄膜時，應力效應會使LBMO薄膜之鐵磁相轉換溫度增加；經過高溫退火的薄膜，其增加的幅度更超越以往的研究結果，無法以單一晶格不匹配的原因來解釋。
本研究藉由二次離子質譜圖和X-ray倒晶格繞射圖分析分析後發現，有部份基板之Sr原子擴散進入薄膜的現象，在固定的高溫退火條件下，Sr原子擴散進入薄膜一定厚度，使厚的薄膜出現上下分層的相分離狀況，而較薄的薄膜則出現近乎完全擴散的狀況。由於擴散區可以視同如混和相La1-x(Ba1-ySry)xMnO3之成份，因而出現高的相轉變溫度，加上原來之不匹配現象，使LBMO薄膜的居禮溫度(TC)上升至以往所未發現的高溫。因此吾人總結發現LBMO薄膜的電性及磁性增現象乃受惠於應力和介面擴散效應之雙重影響所致。

When Colossal Magnetoresistance films are grown on lattice mismatched substrates, the strain on the film/substrate interface induces a strong strain that altered the intrinsic properties on transport and magnetic measurements. The transition temperatures of La0.7Ca0.3MnO3(LCMO) and La0.7Sa0.3MnO3(LSMO) thin films are lowered by both tensile and compress strains, while La0.8Ba0.2MnO3(LBMO) films may be increased or decreased dependent on the type of strains. When La0.8Ba0.2MnO3(LBMO) films were grown on SrTiO3 (STO) substrate by a standard off-axis RF sputtering technique, the compressed strain enhanced the transition temperatures. When La0.8Ba0.2MnO3(LBMO) films were further annealed at higher temperature, the transition temperature was increased up to temperature that was never been achieved, and this phenomena can not be explained solely by the strain effect.
In this study, Secondary ion mass spectroscopy and X-ray reciprocal mapping were used to investigate the possible cause of the extra enhancement in transition temperatures. It is found that under a fixed annealing condition the substrate element, Sr, diffuses partially into the film that separated the films into the top layer and the bottom layer acting as La1-x(SryBa1-y)xMnO3 with higher transition temperature. The TC enhancement can be attributed to the combination of the strain and interdiffusion effects.

摘要
第一章 前言 ‥．‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥1
第二章 基本介紹
2-1 磁阻簡介 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥2
2-2 La1-xBaxMnO3 簡介．‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥5
2-3 Double Exchange Model ．‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥10
2-4 Jahn-Teller distortion ．‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥12
第三章 實驗方法
3-1 射頻濺射鍍膜系統(RF sputtering system) ．‥‥‥‥‥14
3-2 電子束蒸鍍系統(electron-beam gun coater) ．‥‥‥‥16
3-3 電性量測系統 ．‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥17
3-4 超導量子干涉磁化儀 ．‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥20
3-5 二次離子質譜儀(Secondary Ion Mass Spectrometer) ．‥22
3-6 雙晶體X-ray繞射系統 ．‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥24
3-7 原子力顯微鏡(Atomic Force Microscope) ．‥‥‥‥‥26
第四章 數據分析與討論
4-1 結構分析X-ray data ．‥‥‥‥‥‥‥‥‥‥‥‥‥‥28
4-2 電性轉換RT data ．‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥36
4-3 磁性特質MT data ．‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥42
4-4 介面穿隧SIMS data ．‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥46
第四章 結論 ．‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥49
參考資料 ．‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥50

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