為了探討BiFeO3 A-site離子置換後結構、電性、表面形貌(顆粒大小)與磁性之變化，本實驗使用固態反應法(solid state reaction)製成樣品，並量測其結構、介電與磁性特性。在BiFeO3內分別掺入5%La及5%Nd後，結構變化從低溫到高溫依序為菱形晶系(rhombohedral )至長方晶系(orthorhombic)最後轉變為立方晶系(cubic)，且其相變溫度點有明顯不同。此外，La與Nd的掺入皆能有效提升BiFeO3室溫介電常數，並從48.487分別提升至71.045與74.937，同時室溫介電損耗由0.3326降低至0.0127與0.1415。介電常數在600 K~800 K皆有一隨頻率變化的峰值，此現象為反鐵磁到順磁之磁性相變造成的影響，並在菱形晶系晶軸夾角也觀察到相關的變化。

This work is to investigate the structural, electrical, and magnetic properties of various A-site ion substations in BiFeO3. The samples were fabricated by the solid state reaction method (SSR). The experiment methods include the high-resolution synchrotron XRD, dielectric constant, SEM(grain size), and magnetic properties.
The (Bi0.95La0.05)FeO3 and (Bi0.95Nd0.05)FeO3 ceramics exhibit a rhombohedral-orthorhombic-cubic phase transition. The dielectric permittivities of (Bi0.95La0.05)FeO3 and (Bi0.95Nd0.05)FeO3 ceramics are 71.045 and 74.937 at room temperature, respectively. The dielectric loss of (Bi0.95La0.05)FeO3 and (Bi0.95La0.05)FeO3 are about 0.0127 and 0.1415 at room temperature, respectively. The frequency dependent dielectric maximum in 600~800 K is likely activated by the antiferromagnetic transition which takes place at the Néel temperature (TN). This phenomenon associates with a local minimum in rhombohedral distortion angle αR near TN.

目錄
中文摘要…………………………………………………………………i
英文摘要…………………………………………………………………ii
致謝辭…………………………………………………………………iii
圖目錄…………………………………………………………………vi
表目錄…………………………………………………………………ix

第一章　序論……………………………………………………………1
1.1 研究動機……...……………………………………………1
1.2 複鐵性材料 (multiferroics)……………………………..2
1.3 BiFeO3………………………………………………………..3
1.4 文獻回顧……………………………………………………..4
第二章　實驗理論………………………………………………………5
2.1　X-ray繞射原理………………………………………………5
2.1.1　布拉格定律 (Bragg’s law)…………………………5
2.1.2 X-ray特徵光譜………………………………………..6
2.1.3 同步輻射 (synchrotron radiation)……………………7
2.1.4 晶格幾何分析…………………………………………9
2.2 介電常數…………………………………………………….11
2.3 磁性原理…………………………………………………….14
第三章　樣品製備與實驗方法...............................16
3.1 樣品製備……………………………………………………...16
3.1.1 (Bi0.95R0.05)FeO3之調配與球磨………………………16
3.1.2 鍛燒 (calcine)…………………………………………19
3.1.3 高能球磨 (high-energy ball milling)………………20
3.1.4 造粒與成型……………………………………………20
3.1.5 燒結 (sinter)…………………………………………..21
3.2 介電常數量測……………………………………………….22
3.3 X-ray結構量測……………………………………………...23
3.4 SEM量測……………………………………………………23
3.5　磁性量測…………………………………………………….24
第四章 實驗結果與討論………………………………………………25
4.1 結構相變……………………………………………………...25
4.1.1 (Bi0.95La0.05)FeO3…………………………………….25
4.1.2 (Bi0.95Nd0.05)FeO3…………………………………….30
4.2 變溫介電常數分析…………………………………………...35
4.3 SEM量測……………………………………………………43
4.4 磁性量測分析…………………………………….…………..47
第五章 結論……………………………………………………………48
參考文獻………………………………………………………………..50

圖目錄
圖2-1 布拉格繞射………………………………………………………6
圖2-2 電磁波頻譜表……………………………………………………8
圖2-3電子行經磁鐵示意圖…………………………………………….8
圖3-1 研磨球於不同轉速的球磨罐內部運動情形…………………..17
圖3-2 calcined (Bi0.95R0.05)FeO3粉末之室溫XRD………….……19
圖3-3 燒結溫度曲線示意圖…………………………………………..21
圖3-4 sintered (Bi0.95R0.05)FeO3之室溫XRD……………………22
圖4-1 (Bi0.95La0.05)FeO3即時變溫同步輻射XRD…………………27
圖4-2 (a) (Bi0.95La0.05)FeO3 (110)即時變溫同步輻射XRD……27
(b) (Bi0.95La0.05)FeO3 (111)即時變溫同步輻射XRD…………...27
圖4-3 (a) (Bi0.95La0.05)FeO3 (110)升溫過程之d spacing變化....................28
(b) (Bi0.95La0.05)FeO3 (110)升溫過程之d spacing變化………28
圖4-4 (Bi0.95La0.05)FeO3 (110) lattice parameter及晶軸夾角之變化...............................29
圖4-5 (Bi0.95La0.05)FeO3 (111) lattice parameter及晶軸夾角之變化…..29
圖4-6 (Bi0.95Nd0.05)FeO3即時變溫同步輻射XRD…………………….31
圖4-7 (a)(Bi0.95Nd0.05)FeO3 (110)即時變溫同步輻射XRD……………31
(b) (Bi0.95Nd0.05)FeO3 (111)即時變溫同步輻射XRD………..…31
圖4-8 (a) (Bi0.95Nd0.05)FeO3 (110)升溫過程之d spacing變化…….…..32
(b) (Bi0.95Nd0.05)FeO3 (110)升溫過程之d spacing變化………..32
圖4-9 (Bi0.95Nd0.05)FeO3 (110) lattice parameter及晶軸夾角之變化….32
圖4-10 (Bi0.95Nd0.05)FeO3 (111) lattice parameter及晶軸夾角之變化…33
圖4-11 BiFeO3 lattice parameter及晶軸夾角之變化………………….33
圖4-12 (Bi0.95La0.05)FeO3 sintered at 1133K-2hr介電常數與介電損耗隨量測頻率對溫度之關係………………………………………………..36
圖4-13 (Bi0.95La0.05)FeO3 sintered at 1143K-2hr介電常數與介電損耗隨量測頻率對溫度之關係………………………………………………..36
圖4-14 (Bi0.95La0.05)FeO3 sintered at 1153K-2hr介電常數與介電損耗隨量測頻率對溫度之關係……………………………………..…………37
圖4-15 (Bi0.95La0.05)FeO3 sintered at 1163K-2hr介電常數與介電損耗隨量測頻率對溫度之關係………………………………………………..37
圖4-16 (Bi0.95Nd0.05)FeO3 sintered at 1133K-2hr介電常數與介電損耗隨量測頻率對溫度之關係………………………………………….…….39
圖4-17 (Bi0.95Nd0.05)FeO3 sintered at 1143K-2hr介電常數與介電損耗隨量測頻率對溫度之關係………………39
圖4-18 (Bi0.95Nd0.05)FeO3 sintered at 1153K-2hr介電常數與介電損耗隨量測頻率對溫度之關係………………40
圖4-19 (Bi0.95Nd0.05)FeO3 sintered at 1153K-2hr介電常數與介電損耗隨量測頻率對溫度之關係………………40
圖4-20 BiFeO3 sintered at 1133K-2hr介電常數與介電損耗隨量測頻率對溫度之關係…………………………………41
圖4-21 BiFeO3 sintered at 1133 K-2hr SEM表面形態………………43
圖4-22 (Bi0.95La0.05)FeO3 sintered at 1143 K-2hr SEM表面形態……43
圖4-23 (Bi0.95La0.05)FeO3 sintered at 1153 K-2hr SEM表面形態……44
圖4-24 (Bi0.95La0.05)FeO3 sintered at 1163 K-2hr SEM表面形態……44
圖4-25 (Bi0.95Nd0.05)FeO3 sintered at 1133 K-2hr SEM表面形態……45
圖4-26 (Bi0.95Nd0.05)FeO3 sintered at 1143 K-2hr SEM表面形態……45
圖4-27 (Bi0.95Nd0.05)FeO3 sintered at 1153 K-2hr SEM表面形態……45
圖4-28 (Bi0.95Nd0.05)FeO3 sintered at 1163 K-2hr SEM表面形態……46
圖4-29 BiFeO3、(Bi0.95La0.05)FeO3與(Bi0.95Nd0.05)FeO3磁滯曲線關係圖.............................47

表目錄
表2-1 晶格幾何結構關係式........................................................................10
表2-2 不同結構下(110)之d spacing ..............................................................10
表4-1 晶格幾何結構關係式........................................................................26
表4-2 晶格常數與離子半徑........................................................................34
表4-3室溫下(Bi0.95La0.05)FeO3量測頻率100 kHz介電常數與介電損耗....................................38
表4-4室溫下(Bi0.95Nd0.05)FeO3量測頻率100 kHz介電常數與介電損耗....................................42
表4-5室溫下量測頻率100 kHz介電常數與介電損耗......................................................42

[1] James R. Teague, Robert Gerson, and W. J. James, “Dielectrichysteresis in single crystal BiFeO3”, Solid State Commun. 8,1073-1074 (1970).
[2] G. A. Smolenskiĭ, and I. E. Chupis, “Ferroelectromagnets”, Sov. Phys.Usp. 25, 475-493 (1982).
[3] R. Mazumder, S. Ghosh, P. Mondal, Dipten Bhattacharya, S. Dasgupta,N. Das, A. Sen, A. K. Tyagi, M. Sivakumar, T. Takami, and H. Ikuta,“Particle size dependence of magnetization and phase transition nearTN in multiferroic BiFeO3”, J. Appl. Phys. 100, 033908 (2006).
[4] M. Mahesh Kumar, V. R. Palkar, K. Srinivas, and S. V.Suryanarayana, “Ferroelectricity in a pure BiFeO3 ceramic”, Appl.50 Phys. Lett. 76, 2764 (2000).
[5] J.-C. Chen, and J.-M. Wu, “Dielectric properties and ac conductivitiesof dense single-phased BiFeO3 ceramics”, Appl. Phys. Lett. 91,182903 (2007).
[6] B. Ramachandran, and M. S. Ramachandra Rao, “Low temperature magnetocaloric effect in polycrystalline BiFeO3 ceramics”, Appl. Phys.Lett. 95, 142505 (2009).
[7] J. M. Moreau, C. Michel, R. Gerson, and W. J. James, “Ferroelectric BiFeO3 X-ray and neutron diffraction study”, J. Phys. Chem. Solids 32,1315-1320 (1971).
[8] Robert T. Smith, Gary D. Achenbach, Robert Gerson, and W. J. James,“Dielectric Properties of Solid Solutions of BiFeO3 with Pb(Ti, Zr)O3 at High Temperature and High Frequency”, J. Appl. Phys. 39, 70 (1968).
[9] R. Palai, R. S. Katiyar, H. Schmid, P. Tissot, S. J. Clark, J. Robertson, S. A. T. Redferm, G. Catalan, and J. F. Scott, Phys. Rev. B 77, 014110 (2008).
[10] Z.X. Cheng, A.H. Li, X.L. Wang, S.X. Dou, K. Ozawa, H. Kimura, S.J. Zhang, and T.R.Shrout, “Structure, ferroelectric properties, and magnetic properties of the La-doped bismuth ferrite “, J. Appl. Phys. 103, 07E507 (2008).
[11] Zhang, S. T., Zhang, Y., Lu, M. H., Du, C. L., Chen, Y. F., Liu, and Z. G. et al., “Substitution-induced phase transition and enhanced multiferroic properties of Bi1−xLaxFeO3 ceramics“, Applied Physics Letters. 88, 162901 (2006).
[12] R.K. Mishra , Dillip K. Pradhan , R.N.P. Choudhary ,and A. Banerjee, “Dipolar and magnetic ordering in Nd-modified BiFeO3 nanoceramics “, Journal of Magnetism and Magnetic Materials. 320, 2602– 2607 (2008).
[13] Zhongqiang Hu, Meiya Li, Yang Yu, Jun Liu, Ling Pei, Jing Wang, Xiaolian Liu,Benfang Yu, and Xingzhong Zhao, “Effects of Nd and high-valence Mn co-doping on the electrical and magnetic properties of multiferroic BiFeO3 ceramics“,Solid State Communications. 150, 1088-1091 (2010).
[14] Yi Du, Zhen Xiang Cheng, Mahboobeh Shahbazi, Edward W. Collings,Shi Xue Dou, and Xiao Lin Wang, “Enhancement of ferromagnetic and dielectric properties in lanthanum doped BiFeO3 by hydrothermal synthesis”, Journal of Alloys and Compounds 490 637–641 (2010).
[15] S. Karimi, I. M. Reaney, I. Levin, and I.Sterianou, “Nd-doped BiFeO3 ceramics with antipolar order” , Applied Physics Letters. 94, 112903 (2009).
[16] 許樹恩, 吳泰柏, “X光繞射原理與材料結構分析”, 中國材料科學學會 (1996).
[17] C. Kittel, “Introduction to Solid State Physics-8th ed.”, Wiley (2005).
[18] “同步輻射加速器光源”, 國家同步輻射中心
<http://www.nsrrc.org.tw/chinese/img/pdf/info.pdf> (2010).
[19] 金重勳, “磁性技術手冊”,中華民國磁性技術學會 (2002).
[20] 林灯祺, “複鐵性BiFeO3 陶瓷之結構相變與摻BaTiO3 效應” ,天主教輔仁大學物理學系碩士論文 (2010).
[21] Z. X. Cheng, A. H. Li, X. L. Wang, S. X. Dou, K. Ozawa, H. Kimura,S. J. Zhang, and T. R. Shrout, “Structure, ferroelectric properties, and magnetic properties of the La-doped bismuth ferrite”, J. Appl. Phys.103, 07E507 (2008)
[22] D. Lebeugle, D. Colson, A. Forget, M. Viret, P. Bonville, J. F. Marucco, and S. Fusil, “Room-temperature coexistence of large electric polarization and magnetic order in BiFeO3 single crystals”, Phys. Rev. B 76, 024116 (2007).
[23] Qing-hui Jiang, Ce-wen Nan, Yao Wang, Yu-heng Liu, and Zhi-jian Shen, “Synthesis and properties of multiferroic BiFeO3 ceramics”, J. Electroceram 21, 690-693 (2008).
[24] 謝智閔, “高應變(001)切向Pb(Mg1/3Nb2/3)0.70Ti0.30O3單晶的奈米雙晶結構與相轉變” ,天主教輔仁大學物理學系碩士論文 (2008).
[25] 黃世豪, “無鉛鐵電單晶(Na1/2Bi1/2)TiO3的共存與摻錳效應之研究” ,天主教輔仁大學物理學系碩士論文 (2009).
[26] 李慎初, “ 氫離子傳輸Ba(Zr0.8-xCexY0.2)O2.9陶瓷之及時X光繞射研究” ,天主教輔仁大學物理學系碩士論文 (2009).