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狀態NC088FJU00198010
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學校名稱輔仁大學
系所名稱物理學系
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學號487326087
研究生(中)張維倫
研究生(英)Wei Lurn Chang
論文名稱(中)鈮鈦/鈷多層膜物性研究
論文名稱(英)Studies of physical properties of NbTi/Co Mutilayers
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指導教授(中)李尚凡 姚永德
指導教授(英)S.F.Lee Y.D.Yao
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關鍵字(中)鈮 鈷
關鍵字(英)NbTi Co
摘要(中)本論文主題是以濺鍍方式在Si(100)基板上製備NbTi單層膜、NbTi/Co/NbTi與Co/NbTi/Co多層膜,並從它們在電阻性及磁化特性上的表現來探討其超導性與鐵磁性混合的性質,主要使用的量測儀器包括低溫電阻量測系統及SQUID磁量儀。 我們觀察到NbTi單層膜的超導溫度TC會隨其厚度dNbTi的減少而下降;而在dNbTi=4000A時,樣品的TC接近9K與塊材接近,dNbTi=1000A時Tc=8.65k,dNbTi<1000A時Tc快速下降,此種現象與二維薄膜的尺寸效應有關。而對於NbTi300A/CodCo/NbTi300A三層膜,我們原想觀察其TC值隨dCo的增加而振盪的現象,以證明在此結構中是否存在著理論上所預測的π相位波函數,但因實驗條件(濺鍍順序不同)的影響,導致觀察上的困難。 另外,在Co/NbTidNbTi/Co,Co(20A、100A、200A、500A)三層膜中,其TC隨dNbTi變化的趨勢與NbTi單層膜類似,但在dNbTi較薄時,因為Co層對Cooper電子對的拆散效應在此時會較顯著,導致了樣品超導性的降低,因此其TC在dNbTi較薄時會往低溫處偏移。 而對於各組樣品在外加磁場下的磁化曲線圖,低於Tc下量測,我們發現隨著dNbTi (/dCo)的增加,會產生由鐵磁(/超導)性為主的磁滯(/超導磁化)曲線,連續的轉變成由超導(/鐵磁)性為主的超導磁化(/磁滯)曲線。我們可研究磁性對超導性的影響,反應在磁化曲線圖上。我們也可以研究高於TC時,各組樣品在外加磁場下的磁化曲線 是呈現鐵磁性,也可以比較飽和磁矩對鐵磁層厚度變化。 接著我們製作多層膜,研究多層膜與三層膜數據比較,並觀測是否有π相位產生及明顯邊際效應產生。
摘要(英)Single NbTi films, NbTi/Co/NbTi and Co/NbTi/Co Mutilayers were grown on Si(100) substrates at room temperature by dc sputtering method. We discussed their superconductivity and ferromagnetic properties in the mixture from the resistive and magnetic measurements. The main measuring instruments we used were low temperature resistance measuring system and SQUID magnetometer. The value of superconducting transition temperature Tc decreases in general with decreasing dNbTi . Tc~9.0K as dNbTi=4000Å is close to the bulk value. when dNbTi<1000A, Tc decreases very fast. This was related to the finite-size effect of 2D thin-films. For the NbTi/Co/NbTi trilayers, we wanted to verify whether there is oscillation in Tc with increasing dCo, a signature of the π-phase states in this structure predicted in theories. Unfortunately, fluctuation in Tc due to growth condition (sputtering sequence etc.) during deposition process made it difficult for our observation. Otherwise, the dependence of Tc on dNbTi in Co20Å/NbdNbTi/Co20A、 Co100A/NbdNbTi/Co100A、Co200A/NbdNbTi/Co200A and Co500A/NbdNbTi/Co500A trilayers was similar to single NbTi films. For thinner dNbTi, the Tc shifted to lower temperature because of the stronger Cooper pair-breaking effect of Co layers, which led to the reduction of superconductivity. For the hysteresis loops in the whole series of samples which were measured below Tc, the hysteresis loops changed gradually from ferromagnetic (superconductive) ones to superconductive (ferromagnetic) ones when dNbTi(dCo) increased .we used the result to determine relative strength between ferromagnetic and superconductive effects. Otherwise,the hysteresis loops in the whole series of samples which were measured above Tc.The saturation moment per unit volume descreased when dCo decreased. Finally,we compare the results between mutilayers and trilayers data to investigate the proximity effect and if there isπ-phase existing。
論文目次誌謝 中文摘要 Ⅰ 英文摘要 Ⅲ 目錄 Ⅴ 圖目錄 Ⅶ 表目錄 ⅩⅡ 第一章 簡介 1 第二章 超導理論 8 2-1 Meissner效應 8 2-2 二流體模型 11 2-3 Cooper電子對 13 2-4 BCS理論 15 2-5 超導量子干涉 18 2-6 Type Ι與TypeΙΙ超導體 23 第三章 實驗(儀器)原理 27 3-1 薄膜形成之物理機制 27 3-2 濺鍍原理 29 3-3 濺鍍系統· 32 3-4 低溫量測系統 36 3-5 四點量測法 38 3-6 SQUID 41 3-7 探針式膜厚儀 44 3-8 MOKE(磁光科爾效應) 45 3-9 AFM與MFM原理 48 3-10 X-ray繞射原理· 52 第四章 實驗結果 58 4-1 NbTi單層膜之超導性 58 4-2 NbTi/Co/NbTi三層膜超導電性的表現 65 4-3 NbTi/Co/NbTi磁性上的表現 81 4-4 Co/NbTi/Co三層膜超導電性的表現 89 4-5 Co/NbTi/Co磁性上的表現 99 4-6 NbTi/Co多層膜電性與磁性的表現 114 第五章 結論 134 參考文獻 137
參考文獻[1] J. J. Hauser, H. C. Theuerer, and N.R.Werehamer, Phys.Rev.142, 118(1966) [2] L. H. Greene, W. L. Feldmann, J. M. Rowell, B.Batlogg, E.M.Gyorgy, W. P. Lowe, and D.B.McWhan, Superlattices Microstruct.1, 407(1985) [3] G. Verbanck, C.D. Potter, R. Schad, P. Belien, V.V. Moshchalkov and Y.Bruynseraede, Physica C 235-240 3295-3296(1994) [4] G. Verbanck, C.D. Potter, V. Metlushko, R. Schad, V.V. Moshchalkov and Y. Bruynseraede, Phys.Rev.B57, 6029(1998) [5] Th. Muhge, N.N.Garifyanov, Yu.V.Goryunov, K.Theis-Brohl, Physica C 296, 325-336(1998) [6] K. Kawaguchi and M.Sohma, Phys.Rev.B46, 14722(1992) [7] P. Koorevaar, Y. Suzuki, R. Coehoorn, and J. Aarts, Phys.Rev.B49,441(1994) [8] H. K. Wong, B. Y. Jin, H. Q.Yang, J. B. Ketterson, and J. E. Hilliard, J.Low Temp.Phys. 63, 307(1986) [9] H. K. Wong and J. B. Ketterson, J. Low Temp.Phys. 63, 139(1986) [10] Ctirad Uher and Joshua L.Cohn, Phys.Rev.B34, 4906(1986) [11] Ctirad Uher and Roy Clarke, Phys.Rev.B30, 453(1984) [12] C. Strunk, C.Surgers, U.Paschen, and H.von Lohneysen, Phys.Rev.B49,4053(1994) [13] C. Attanasio, C.Coccorese, L.Maritato, M.Salvato, L.Maritato,Phys.Rev.B57, 6056(1998) [14] J. E. Mattson, R.M. Osgood III, C.D.Potter, C.H.Sowers, and S.D.Bader,J.Vac. Sci Technol. A15(3), 1774(1997) [15] H. Homma, C.S.L.Chun, G.G.Zheng, and Ivan K. Schuller, Phys.Rev.B33, 3562(1986) [16] ADVANCES IN PHYSICS, Vol.38, No.3, 189-366.1989 [17] Shinjo, Takada, ”METALLIC SUPERLATTICES(Artificially Structured Materials)”, p187-211(1987) [18] J. S. Jiang, D.Davidovic, D.H.Reich, and C.L.Chien, Phys.Rev.Lett.74,314(1995) [19] J. S. Jiang, D.Davidovic, D.H.Reich, and C.L.Chien, Phys.Rev.B54,6119(1996) [20] L. V. Mercaldo, C.Attanasio, C.Coccorese, L.Maritato, S.L.Prischepa,and M. Salvato, Phys.Rev.B53, 14040(1996) [21] R. Fazio and C.lucheroni, Europhys.Lett, 45(6), P707-713(1999) [22] K. Kuboya and K.Takanaka, Czech.J.Phys.46, S2583(1996) [23] L.R.Tagirov,Physica C 307,145~163(1998) [24] Th. Muhge, N.N.Garityanov, Yu.N.Goryunov, G.G.Khaliullin, L.R.Tagirov, K.Westerholt, I.A.Garifullin, and H.Zabel, Phys.Rev.Lett.77, 1857(1996) [25] Th. Muhge, K.Westerholt, H.Zabel, N.N.Garityanov, Yu.N.Goryunov, and I.A.Garifullin, G.G.Khaliullin, Phys.Rev.B55, 8945(1997) [26] 張裕恆、李玉芝, 民81, “超導物理”, p25, p15, 儒林圖書公司 [27] 方俊鑫, 民79, “固態物理學(下)”, p329, 亞東書局 [28] 張裕恆、李玉芝, 民81, “超導物理”, p32, 儒林圖書公司 [29] 張裕恆、李玉芝, 民81, “超導物理”, p333, 儒林圖書公司 [30] C. Kittel, 1996, “Introduction to Solid State Physics 7th edit”, p354, Wiley [31]B. D. Josephson, Phys.Letts. 1251(1962) [26] C. Kittel, 1996, “Introduction to Solid State Physics 7th edit”, p340, Wiley [33] 呂助增, 民79, “實驗物理方法”, p256, 聯經出版社 [34]呂助增, 民79, “實驗物理方法”, p261, 聯經出版社 [35]施文泰, 民88,p46,碩士論文集 [36]施文泰, 民88,p45,碩士論文集 [37] ADVANCES IN PHYSICS, Vol.38, No.3, p222.1989 [38] E.W.Collings,``Applied Superconductivity Metallurgy,and Physics of Titanium Alloys’’,p423 ,1983 [39]C.L.Chien,Daniel,H.reich,JMMM200,83-94(1999)
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