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研究生:曾彥豪
研究生(外文):Yan-Hao Tseng
論文名稱:用分子束磊晶成長Mn3-xMgxO4(x=0,0.6)薄膜於MgO(100)及(110)之表面皺化現象與磁性分析
論文名稱(外文):Faceting and magnetic response of Mn3-xMgxO4 (x=0 and 0.6) thin films grown on MgO(001) and (011) by molecular beam epitaxy
指導教授:陳恭陳恭引用關係
指導教授(外文):Gung Chern
學位類別:碩士
校院名稱:國立中正大學
系所名稱:物理所
學門:自然科學學門
學類:物理學類
論文種類:學術論文
論文出版年:2008
畢業學年度:96
語文別:中文
論文頁數:65
中文關鍵詞:皺化氧化錳
外文關鍵詞:Mn3O4facet
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Mn3O4塊材具有非線性磁性結構(Noncollinear magnetic structure),一般認為可能是產生磁電效應(Magnetodielectric effect)的原因。論文中我們使用分子束磊晶(MBE)在MgO(100)及(110)基板上低溫250C成長Mn3-xMgxO4(x=0、0.6、1.4)薄膜並探討其結構與磁性。經過X-ray分析之後,成長在MgO(100)及(110)的Mn3-xMgxO4薄膜均為單晶結構,藉由X-ray繞射分別分析(004)及(202)平面得知,a與c軸的晶格常數隨x增加而逐漸接近,代表長方體的結構將成為正方體結構;透過掃描式顯微鏡(SEM)來觀察成長於MgO(100)及(110)基板上之Mn3O4薄膜的表面,發現MgO(100)上的薄膜表面產生方形(111)平面皺化(faceting)現象,皺化程度約為110nm;MgO(110)基板上為長條型的(100)平面皺化,其皺化的長度約為280nm,寬約為27nm。磁性的量測初步顯示出,Mn3O4薄膜的飽和磁化量(Ms)約為1.8μb,居禮溫度為44 K,皆與塊材相當接近,代表磁性結構應該也可能是非線性的磁性結構,預期可能也具備有磁電效應(Magnetodielectric effect)。但在磁滯曲線中卻發現有階梯狀磁滯曲線,原因即是Mn3-xMgxO4(x=0)薄膜的表面皺化現象所導致;我們藉由添加Mg來降低薄膜的表面能,但隨著x的增加(x=0.6,1.4),居禮溫度有下降的趨勢,但皺化的現象卻獲得改善。此
外,Mn2.4Mg0.6O4的Ms下降為~1μb,Ms的下降除了Mg離子的取代,也可能是由於自旋間耦合角度的改變,此議題值得未來更深入的探討。
Mn3O4 has noncollinear magnetic structure which may induce magnetodielectric effect. We extend to study Mn3-xMgxO4 (x=0 and 0.6) thin films grown on MgO(100) and MgO(110) substrates by molecular beam epitaxy. The growth temperature is at 250 C and the film thickness is 200 nm. X-ray diffraction along (001) direction reveals epitaxial quality and the structure transition for all films. The structure of Mn3-xMgxO4 thin films undergoes a transition from a tetragonal spinel to cubic structure as x increase. However, scanning electron microscopy (SEM) observes facets forming in (111) and (100) planes for the films grown on MgO(100) and MgO(110), respectively. The shapes for the (111) facet are square with average side length ~ 110 nm while the shapes for the (100) facet are elongated with average width ~ 27 nm and the length as long as ~ 280 nm. The magnetization vs. temperature (M-T) measurement shows ferromagnetic response and the Curie temperature ~ 44 K. The saturation magnetization (Ms) at 6 K is ~ 1.8 μb which is similar to the bulk value. However, stepped hysteresis loops are observed indicating a mixed magnetic response due to the faceting structure. SEM results further reveals that the surface faceting effects are substantially suppressed for Mn2.4Mg0.6O4 film. The Ms is ~1.02μb and Cure temperature of these films drops to ~30K. Mg ions replace Mn ions in both A and B sites and form a mixed spinel structure in Mn2.4Mg0.6O4 film. The substitution of Mn by Mg clearly reduces the surface energy and also weakens the exchange coupling of Mn3-xMgxO4 thin films. However, the noncollinear magnetic structure still remains in Mn3-xMgxO4 thin films.
第1章. 簡 介 1
1-1 前言 1
第2章. 理 論 背 景 3
2-1 結構及磁性簡介 3
2-1-1. 陶鐵磁性物質 3
2-1-2. Spinel結構 4
2-1-3. MgO結構 7
2-1-4. 亞鐵磁的磁性 9
2-2 皺化現象(Faceting) 14
第3章. 實驗儀器與實驗步驟 16
3-1 分子束磊晶系統(molecular beam epitaxy) 17
3-2 物理性質量測系統 (Physical Properties Measurement System) 26
3-3 X-ray 繞射儀 29
3-4 掃描式電子顯微鏡(Scanning Electron Microscopy) 31
3-5 實驗步驟 32
第4章. 實驗結果與討論 34
4-1 晶體結構的量測結果與討論 35
4-2 SEM的量測結果與討論 41

4-3 PPMS量測結果與討論 47
4-4 薄膜飽和磁化量與Mg添加量的關係 59
第5章. 結 論 62
References 64
[1] D. Adler, Solid State Phys. 21, 1(1968)
[2] I. S. jacobs, J. phys. Chem. Solids 11, 1 (1959)
[3] Kirby dwight and Norman menyuk, physical review 119,1470
(1960)
[4] R. Tackett,G. Lawes,Phys.Rev.B 76,024409 (2007)
[5] Kittel “introduction to solid state physics”,8th ed. ( John Wiley & Sons; 8th edition, 2005) P337
[6] E.P.Wohlfarth,”Ferromagnetic Material”(North-Holland, 1980) P241-251
[7] Sushin Chikazumi, “Physics of magnetism”( John Wiley & Sons; 1st edition, 1964) P79
[8] Sushin Chikazumi, “Physics of Ferromagnetism” (Oxford University Press, USA; 2 edition ,April 24, 1997) P207
[9] 黃健彰,碩士論文,中正大學(86級)
[10] Some reviews of faceting are given by J.J. Lander, in Progress in Solid State Chemistry,Ed.H.Reiss(Pergamon, Oxford, 1965);and by J.M.May, in Advance in Catalysis and Related Subjects, Vol 21, Ed. W.G. Frankenburg et al.(Academic, New York, 1970)
[11] A.U. MacRae, Bull. Am. Phys. Soc.10, 68(1965)
[12] R.J. Phaneuf, and E.D. Williams, phys. Rev. Lett.52, 2563(1987)
[13] R.J. Phaneuf, N.C. Bartelt, E.D. Williams, W.Swiech and E. Bauer, phys. Rev. Lett. 67,2986(1991)
[14] S.Folsh, A.Helms, S.Zophel, J.Repp, G.Meyer, and K.H.Rieder, Phys. Rev. Lett. 84,123(2000)
[15] 李秉傑, 科儀新知, 第十三卷第四期, P28(1992)
[16] 王耿敏,碩士論文,中正大學(92級)
[17] 李淑媚,碩士論文,中正大學(88級)
[18] 洪英哲,碩士論文,中正大學(94級)
[19] 劉伊郎,碩士論文,中正大學(90級)
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