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研究生： 何榮浩
He, Rong-Hao
論文名稱： 利用自旋幫浦探討CrTe2/Py 以及銅傳輸層對自旋電荷轉換效率之研究
The spin-to-charge conversion efficiency in CrTe2/Py and copper interlayer effects using spin pumping measurements
指導教授： 黃榮俊
Huang, Rong-Jun
學位類別： 碩士
Master
系所名稱： 理學院 - 物理學系
Department of Physics
論文出版年： 2023
畢業學年度： 111
語文別： 中文
論文頁數： 66
中文關鍵詞： 自旋電荷轉換效率 、自旋幫浦效應 、逆埃德爾施泰因效應 、超導量 子干涉儀 、拉曼光譜 、CrTe2
外文關鍵詞： spin-to-charge conversion efficiency, spin pumping effect, Inverse Edelstein Effect, SQUID, Raman, CrTe2
相關次數： 點閱：138  下載：12 
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    • 在本實驗中，我們研究了CrTe2/Py 系統中的自旋電荷轉換效率。我們利用微波促使 Py 層發生鐵磁共振進而產生自旋流，並藉由自旋幫浦效應讓自旋流注入至CrTe2層，因為強自旋軌道效應所造成的逆埃德爾施泰因效應(Inverse Edelstein Effect)將自旋流轉換至電流。首先我們先針對CrTe2進行超導量子干涉儀和拉曼量測實驗，觀察CrTe2的磁性和分子震盪模式。接著我們會改變CrTe2的厚度並比較不同厚度的CrTe2在自旋電荷轉換效率上會有何差異，發現當CrTe2的厚度比較薄的時候，其轉換效率較高，而隨著CrTe2厚度增加時，其轉換效率則遞減，表示很可能當CrTe2的厚度增加時，CrTe2的塊材態（bulk state）影響會隨之增加，介面態（interface state）影響會變小，因此轉換效率才會跟著變小。再來我們在介面插入不同厚度的銅傳輸層，觀察銅傳輸層對轉換效率的影響，結果是插入銅傳輸層後對轉換效率無增益效應，我們猜測有可能是因為銅傳輸層破壞了 Rashba 介面。而我們的研究將對於 CrTe2 在自旋電子學的應用有所貢獻。

    In this study, The spin-to-charge conversion efficiency of CrTe2/Py was investigated
    using the spin pumping technique. The microwave-induced ferromagnetic resonance in the Py layer generated a spin current, which was subsequently injected into the CrTe2 layers and converted to a charge current due to the Inverse Edelstein Effect. First, we will change the thickness of CrTe2 and compare the difference in conversion efficiency with different thicknesses. Then insert a copper transport layer of different thicknesses at the interface, and then observe the influence of the copper transport layer on the conversion efficiency. The result is that the insertion of the copper transport layer does not seem to help the conversion efficiency. We guess that maybe the surface state of Rashba interface is destroyed by the copper transport layer. In addition, we also perform SQUID and Raman measurements of CrTe2 and learn the magnetic properties and molecular oscillation modes of CrTe2.

    摘要 I Abstract II SUMMARY II INTRODUCTION II METHODS III RESULTS AND DISCUSSION IV Conclusion VIII 誌謝 IX 目錄 X 圖目錄 XIII 第一章、緒論 1 1-1前言 1 1-2文獻回顧 2 1-2-1文獻一 2 1-2-2文獻二 5 1-3研究動機 7 第二章、實驗相關理論原理 8 2-1鐵磁共振與自旋幫浦效應 8 2-2電流—自旋流轉換 11 2-2-1自旋霍爾效應（Spin Hall Effect, SHE） 11 2-2-2逆自旋霍爾效應（Inverse Spin Hall Effect, ISHE） 11 2-2-3 Edelstein effect 12 2-2-4 Inverse Edelstein effect 13 2-3磁性 14 2-3-1鐵磁性（Ferromagnetism） 14 2-3-2亞鐵磁性（Ferrimagnetism） 15 2-3-3順磁性（Paramagnetism） 15 2-3-4反鐵磁性（Anti-ferromagnetism） 16 2-3-5抗磁性（diamagnetism） 17 第三章 實驗儀器介紹 19 3-1分子束磊晶系統（Molecular Beam Epitaxy, MBE） 19 3-1-1準備腔（Prepare Chamber） 20 3-1-2傳輸腔（Load Lock Chamber） 20 3-1-3成長腔（Growth Chamber） 20 3-1-4蒸鍍分子源（Knudsen Cell） 21 3-1-5分子束流量計（Beam Flux Monitor, BFM） 21 3-1-6石英震盪膜厚計（Quartz Crystal Microbalance, QCM） 21 3-1-7反射式高能電子槍（RHEED） 22 3-2離子束濺鍍系統（Ion Beam Sputtering, IBS） 23 3-2-1傳輸腔 23 3-2-2成長腔 24 3-2-3離子束發射源 24 3-3 X光繞射儀（X-ray diffractometer, XRD） 25 3-4 X光反射率（X-ray reflectivity, XRR） 26 3-5超導量子干涉儀（Superconducting Quantum Interference Device Vibrating Sample Magnetometer, SQUID VSM） 27 3-6自旋幫浦系統 28 3-7四點電阻量測 29 3-8拉曼光譜儀 30 第四章、實驗流程和數據處理 31 4-1 CrTe_2製備 31 4-1-1基板前置處理 31 4-1-2 MBE長膜 31 4-2 Cu和Py製備 32 4-3鐵磁共振數據處理 33 第五章、實驗結果與分析 38 5-1 CrTe_2的Raman量測結果分析 38 5-2 CrTe_2的SQUID量測結果分析 39 5-3 CrTe_2的Spin pumping量測結果分析 46 5-3-1 CrTe_2厚度對spin pumping之影響 46 5-3-2銅傳輸層對CrTe_2的spin pumping之影響 57 第六章、結論 64 參考資料 65

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