反鐵磁與鐵磁介面的交換耦合偏移效應是發展自旋電子科技的關鍵之一。化學有序結構的FeRh在室溫附近，可藉由加熱至370 K具有反鐵磁相轉變成鐵磁相之第一磁相變的性質，此磁相變往往伴隨著體積的膨脹、電阻的改變、巨大磁熵的改變。本論文利用磁控濺鍍方式製備FeRh薄膜，選用兩種不同基板，一是MgO基板，另一為SrTiO3基板鍍上BaTiO3當作緩衝層，並經過不同溫度的熱退火處理，以及厚度的改變，比較兩者的不同。並且展示反鐵磁相與鐵磁相之間的磁特性及結構等變化，透過X光繞射、 X光反射率量測、掃描式電子顯微鏡、物理性質量測系統量測FeRh薄膜，分析其晶體結構、序化程度、厚度、磁性、電性等性質。特別的是在磁性分析上觀察到交換耦合偏移現象。這是第一次在同質材料中觀察到異質介面的交換耦合偏移現象。推測其一可能的原因為應力造成FeRh薄膜有不同層，另一原因為高溫退火下，造成基板與材料之間原子的擴散，最後可能造成FeRh本身具有不同相變溫度。

The exchange bias effect at ferromagnetism (FM)/antiferromagnetism(AFM) interface is a key on developing spintronic technologies with new functionality. It is well known that chemically ordered FeRh alloys with the CsCl structure show the fascinating first order magnetic phase transition from the antiferromagnetic to ferromagnetic states at around 370 K upon heating from room temperature, accompanied by an isotropic volume expansion of about 1%, a large reduction in the resistivity and a large change in entropy. FeRh thin films were prepared by magnetron sputtering on MgO(001) substrates and annealed in the temperature range of 700-900 ℃. The structure was characterized by X-ray diffraction and it showed an epitaxial FeRh thin film on MgO(001) substrates and on BaTiO3 buffered SrTiO3(001) substrates. In this paper, the structures and magnetic properties of phase transition are analyzed by using X-ray diffraction, X-ray reflectivity, scanning electron microscope and physical property measurement system. In particular, here we probe the AFM/FM of FeRh interface magnetization, and identify a new exchange bias phenomena. This is the first homogenous system with exchange bias without having a hetergenous interface of FM/AFM layer. One of the possible reason is due to the strain at interface which induced an AFM FeRh layer under the FM FeRh layer. The other possibility could be due to the interdiffusion of atoms from neighboring layer into FeRh at higher temperature resulting in change of FM/AFM phase transition temperature, so that AFM is formed in the heavy doped FeRh layer under the FM FeRh layer.

摘要 i
Abstract ii
致謝 iii
目錄 iv
表目錄 vii
圖目錄 ix
第一章 緒論 1
1.1前言 1
1.2 磁性基本理論 2
1.2.1 物質磁性的分類 2
1.2.2 交換磁異相性 4
1.3 FeRh的特性 5
1.4 FeRh的應用 8
1.4.1 熱輔助磁紀錄 8
1.4.2 磁致冷卻 9
1.5文獻回顧 10
1.5.1 磁場對相轉變的影響 10
1.5.2 摻雜微量元素對相轉變的影響 11
1.5.3 結構對相轉變的影響 12
1.5.4 應力對相轉變的影響 14
1.6動機 16
第二章 實驗方法 17
2.1實驗儀器與原理 17
2.1.1濺鍍系統(Sputtering System) 17
2.1.1.1直流濺鍍(DC Sputtering) 17
2.1.1.2交流濺鍍(RF Sputtering) 18
2.1.1.3磁控濺鍍(Magnetron Sputtering) 19
2.1.4掃描式電子顯微鏡 (Scanning Electron Microscope) 20
2.1.5同步輻射(Synchrotron Radiation) 22
2.1.6 X光繞射(X-ray Diffraction) 23
2.1.7 X光反射率(X-ray Reflectivity) 25
2.1.8 物理性質量測系統(Physical Properties Measurement) 27
2.2薄膜之製備 28
2.2.1 FeRh單層不同退火溫度之製成參數 28
2.2.2 FeRh單層不同退火厚度之製成參數 29
2.2.3 FeRh與BTO雙層不同退火溫度之製成參數 30
2.2.4 FeRh與BTO雙層FeRh不同厚度之製成參數 31
第三章 結果與討論 32
3.1 FeRh單層不同退火溫度之分析 32
3.1.1 XRD分析 32
3.1.2 XRR與SEM分析 42
3.1.3電性分析 46
3.1.4磁性分析 48
3.2 FeRh單層不同退火厚度之分析 50
3.2.1 XRD分析 50
3.2.2 磁性分析 54
3.3 FeRh與BTO雙層不同退火溫度之分析 55
3.3.1 XRD分析 55
3.4 FeRh與BTO雙層不同FeRh厚度之分析 61
3.4.1 XRD分析 61
3.4.2 SEM cross section & XRR 66
3.4.3電性分析 68
3.4.4磁性分析 70
第四章 結論 74
未來展望 75
文獻參考 76
附錄 79

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