臺灣博碩士論文加值系統

　BiFeO3(統稱BFO)具有很高的居禮溫度TC(~850℃)和尼爾溫度TN(~370℃)，在室溫下同時擁有鐵電性和反鐵磁性質，是目前最富潛力的複鐵性材料之一。但因其較大漏電流和製程產生之雜相，使其鐵電性質較差。
本論文探討BFO分別以La取代Bi和Ti取代Fe，對BFO性質的影響與改變。Bi3+離子和La3+離子半徑相近，Ti4+離子和Fe3+離子半徑亦相近，故本論文希望在BFO鈣鈦礦結構中，藉由La3+離子取代Bi3+離子和Ti4+離子取代Fe3+離子來改善BFO漏電流過大的問題。
　　我們利用固態反應法製作出BFO塊材和分別摻雜La3+離子和Ti4+離子的BFO塊材，利用導電率量測、漏電流量測、XRD、XPS，並輔以第一原理計算缺陷形成能、bader charge、能態密度(Density of state)，探討不同元素摻雜對BFO其缺陷形成與漏電流機制的影響。

BiFeO3 (BFO), which is one of the most potential multiferroics ,has high Curie temperature TC(~1100 K) and high Néel temperature TN(~643 K) resulting to the coexistence of ferroelectricity and ferromagnetism at room temperature.
This study mainly reported the influence and change by the doping of lanthanum and Titanium.Bi3+ ions have close size as La3+ ions, and Fe3+ ions have close size as Ti4+ ions, so we hope to reduce the leakage current with the substitution of La3+ ions for Bi3+ ions and Ti4+ ions for Fe3+ ions in the perovskite BiFeO3 structure.
Bulks of BiFeO¬3 and BiFeO3 doping with La3+ or Ti4+ were prepared by the usual solid state reaction method. X-ray diffraction(XRD), conductivity measurements ,leakage current measurements, X-ray photoelectron spectroscopy(XPS) are utilized and supplemented by first-principles calculation of defect formation energies, Bader charge, the density of states (DOS),to discuss its impact on the BFO leakage defect formation mechanisms with different doping.

中文摘要 I
英文摘要 II
誌謝 VII
總目錄 VIII
表目錄 X
圖目錄 XI
第一章 緒論 1
1-1 前言 1
1-2 研究動機與方向 2
第二章 理論基礎及文獻回顧 4
2-1 鐵電材料 4
2-2 磁性材料 8
2-3 漏電流機制 12
2-4 BiFeO3的晶體結構 15
2-5 BiFeO3相圖 18
2-6 BiFeO3的鐵電性 18
2-7 模擬基礎理論 21
第三章 實驗設計與模擬方法 23
3-1實驗藥品 23
3-2　BiFeO3粉末製備方法 23
3-3　BiFeO3塊材製備 25
3-4 BiFeO3製程流程圖 26
3-5 計算模型建置 27
3-6 形成能計算 30
第四章 結果與討論 31
4-1 XRD結構分析 31
4-2 缺陷形成能(defect formation energy)與電荷分析(bader charge analysis) 35
4-3 XPS分析 37
4-4 導電機制分析 41
第五章 結論 45
參考文獻 46

[1] J. B. N. J. Wang, H. Zheng, V. Nagarajan, S. B. Ogale, , Epitaxial BiFeO 3 Multiferroic Thin Film Heterostructures, Science, vol. 299, pp. 1719-1721, 2003.
[2] S. W. O. G.L. Yuan, Y.P. Wang,Z.G. Liu, Preparation and multi-properties of insulated single-phase BiFeO 3 ceramics, Solid State Communications, vol. 138, pp. 76-81, 2006.
[3] L. Z. Y. P. Wang, M. F. Zhang, X. Y. Chen, J.-M. Liu, and Z. G. Liu, Room-temperature saturated ferroelectric polarization in BiFeO3 ceramics synthesized by rapid liquid phase sintering, APPLIED PHYSICS LETTERS, vol. 84, 2004.
[4] K. Z. A. K. Pradhan, D. Hunter, J. B. Dadson, G. B. Loiutts, P. Bhattacharya, R. Katiyar, Jun Zhang, D. J. Sellmyer, U. N. Roy, Y. Cui, and A. Burger Magnetic and electrical properties of single-phase multiferroic BiFeO 3, JOURNAL OF APPLIED PHYSICS, vol. 97, 2005.
[5] N. M. Antonio Perej′on, Pedro E. S′anchez-Jim′enez,Jos′e M. Criado,Jan Subrt,Mar′a J. Di′anezand Luis A. P′erez-Maqueda* a, Direct mechanosynthesis of pure BiFeO 3 perovskite nanoparticles: reaction mechanism＋, Materials Chemistry C, 2013.
[6] X. Z. Qiang Zhang, Yunhui Xu, Haobin Gao, Yunjun Xiao, Dayun Liang,Jiliang Zhu, Jianguo Zhu, Dingquan Xiao, Effect of La3+ substitution on the phase transitions, microstructure and electrical properties of Bi 1-x Lax FeO 3 ceramics, Journal of Alloys and Compounds vol. 546, pp. 57-62, 2013.
[7] A. H. L. Z. X. Cheng, X. L. Wang, S. X. Dou, K. Ozawa Structure, ferroelectric properties, and magnetic properties of the La-doped bismuth ferrite, APPLIED PHYSICS vol. 103, 2008.
[8] T.-T. F. Ju Hong Miao, Effect of La Doping on the Phase Conversion, Microstructure Change,and Electrical Properties of Bi 2 Fe 4 O 9 Ceramics, Communications of the American Ceramic Society, vol. 92, pp. 2762-2764, 2009.
[9] X. D. Qi, J. Dho, R. Tomov, M. G. Blamire, and J. L. MacManus-Driscoll, Greatly reduced leakage current and conduction mechanism in aliovalent-ion-doped BiFeO3, Applied Physics Letters, vol. 86, Feb 7 2005.
[10] S. L. Ruipeng Yang, Xiaogong Fang,Xingsen Gao,Min Zeng,, First-principles study on the magnetic properties in Mg doped BiFeO 3 with and without oxygen vacancies, JOURNAL OF APPLIED PHYSICS, vol. 114, 2013.
[11] R. P. Y. L. Y. Zou, Y. B. Lin, M. H. Qin, X. S. Gao, M. Zeng, and J.-M. Liu Dielectric and magnetic properties of BiFe1-4x/3TixO3 ceramics with iron vacancies: Experimental and first-principles studies, JOURNAL OF APPLIED PHYSICS, vol. 114, 2013.
[12] M.-A. E. Sverre M. Selbach, and Tor Grande*, On the Thermodynamic Stability of BiFeO, Chem. Mater, vol. 21, 2009.
[13] M. S. Bernardo, T. Jardiel, M. Peiteado, F. J. Mompean, M. Garcia-Hernandez, M. A. Garcia, et al., Intrinsic Compositional Inhomogeneities in Bulk Ti-Doped BiFeO3: Microstructure Development and Multiferroic Properties, Chemistry of Materials, vol. 25, pp. 1533-1541, 2013/05/14 2013.
[14] M. J. A. A. R. Makhdoom, M. A. Rafiq, M. Siddique, M. Iqbal, and M. M. Hasan Enhancement in the multiferroic properties of BiFeO3 by charge compensated aliovalent substitution of Ba and Nb, AIP ADVANCES, vol. 4, 2014.
[15] J.-M. M. Christian Michel, Gary D. Achenbechi, Robert Gerson, and W.J. James, THE ATOMIC STRUCTURE OF BiFeO3, Solid State Communications, vol. 7, pp. 701-704, 1969.
[16] M. P. P Fischerl., I Sosnowskag and M Szymanskig Temperature dependence of the crystal and magnetic structures of BiFeO, Solid St. Phys, vol. 13, pp. 1931-1940, 1980.
[17] R. G. a. W. J. J. James R. Teague, DIELECTRIC HYSTERESIS IN SINGLE CRYSTAL BiFeO3, Solid State Communications, vol. 8, pp. 1073-1074, 1970.
[18] D. C. D. Lebeugle, A. Forget, M. Viret, P. Bonville, J. F. Marucco, and S. Fusil, Room-temperature coexistence of large electric polarization and magnetic order in BiFeO 3 single crystals, PHYSICAL REVIEW B, vol. 76, 2007.
[19] J. W. Jiefang Li, M. Wuttig, R. Ra, Dramatically enhanced polarization in ( 001 ) , ( 101 ) , and ( 111 ) BiFeO 3 thin films due to epitiaxial-induced transitions
APPLIED PHYSICS LETTERS, vol. 84, 2004.
[20] J. A. S. DAVID S. SHOLL DENSITY FUNCTIONAL THEORY A Practical Introduction, 2009.
[21] G. A. B. S. L. Dudarev, S. Y. Savrasov,C. J. Humphreys,A. P. Sutton, Electron-energy-loss spectra and the structural stability of nickel oxide: An LSDA 1 U study, PHYSICAL REVIEW B, vol. 57, pp. 1505-1509, 1998.
[22] R. M. M. In-Ho Lee, Applications of the generalized-gradient approximation to atoms, clusters, and solids, PHYSICAL REVIEW B, vol. 56, pp. 7197-7205, 1997.
[23] I. G. V. Antonov, N. Trendalova, D. Kovacheva, K. Krezhov, First principles study of structure and properties of La- and Mn-modied BiFeO3, Solid State Sciences vol. 14, pp. 782-788, 2012.
[24] J. E. S. Yi Wang, Pingping Wu, Jianjun Wang, Shunli Shang, Zi-Kui Liu,Long-Qing Chen, First-principles lattice dynamics and heat capacity of BiFeO 3, Acta Materialia, vol. 59, pp. 4229-4234, 2011.
[25] L.-M. P. S. L. Dudarev, S. Y. Savrasov,J.-M. Zuo, Correlation effects in the ground-state charge density of Mott insulating NiO: A comparison
of ab initio calculations and high-energy electron diffraction measurements, PHYSICAL REVIEW B, vol. 61,, pp. 2506-2512, 2000.
[26] S. J. a. T.-Y. Cai, First-principles studies of the effect of oxygen vacancies on the electronic structure and linear optical response of multiferroic BiFeO 3, APPLIED PHYSICS LETTERS, vol. 95, 2009.
[27] Y. Y. F. Gao, K. F. Wang, X. Y. Chen, F. Chen et al. , Preparation and photoabsorption characterization of BiFeO 3 nanowires, APPLIED PHYSICS LETTERS, vol. 89, 2006.
[28] P. W. Zhen Zhang, Lang Chen, and Junling Wang Density functional theory plus U study of vacancy formations in bismuth ferrite, APPLIED PHYSICS LETTERS, vol. 96, 2010.
[29] K. S. P. S piewak, J. Vanhellemont, K.J. Kurzyd owski, Ab initio calculation of the formation energy of charged vacancies in germanium, Physica B, vol. 401-402, pp. 205-209, 2007.
[30] T. H. a. H. Moriwake, Oxygen vacancy formation energy and its effect on spontaneous polarization in Bi 4 Ti 3 O 12 :A rst-principles theoretical study, PHYSICAL REVIEW B vol. 78, 2008.
[31] T.A.Stolyarova, ROLE OF OXYGEN CHEMICAL POTENTIAL IN THERMODYNAMICS OF MINERALS OF APATITE GROUP 2000.
[32] A. C. Xiao-Gang Wang 1 , 2 , Matthias Scheer, The Eect of the Environment on α -Al 2 O 3 (0001) Surface Structures, 2008.
[33] V. I. N. L. A. Klinkova , N. V. Barkovskii , and V. K. Fedotov Thermal Stability of Bi 2 O 3, Russian Journal of Inorganic Chemistry, vol. 52, pp. 1822–1829, 2007.
[34] N. S. M. a. D. G. Zetaruk, X-ray Photoelectron Spectroscopic Studies of Iron Oxides ANALYTICAL CHEMISTRY, vol. 49, 1977.
[35] B. A. K. A. P. Grosvenor, M. C. Biesinger and N. S. McIntyre, Investigation of multiplet splitting of Fe 2p XPS spectra and bonding in iron compounds, SURFACE AND INTERFACE ANALYSIS, vol. 36, pp. 1564-1574, 2004.
[36] G. T. Xu Xue, Wenlong Liu, Huijun Ren, Comparative study on multiferroic (Bi 0.9 RE 0.1 )(Fe 0.97 Co 0.03 )O 3 δ(RE ¼ Ce and Ho) thin lms: Structural, electrical and optical properties, Ceramics International, vol. 40, pp. 6247-6254, 2014.
[37] W. F. Dr in. Andrzej Osak, Matematyki i Informatyki Stosowanej, Politechnika Krakowska. , STUDIES OF THE DC AND AC HOPPING ELECTRICAL CONDUCTIVITY IN FERROELECTRIC Pb[(Fe 1/3 Sb 2/3 ) X Ti Y Zr Z ]O 3 fundamental sciences, 2011.
[38] K. A. M. E Veena Gopalan , S Saravanan , D Sakthi Kumar ,Yasuhiko Yoshida and M R Anantharaman, Evidence for polaron conduction in nanostructured manganese ferrite, APPLIED PHYSICS, vol. 41, 2008.
[39] A. Ghosh, ac conduction in iron bismuthate glassy semiconductors, PHYSICAL REVIEW B, vol. 42, pp. 1388-1393, 1990.
[40] S. M. A. T.M. Meaz Effect of tetravalent titanium ions substitution on the dielectric properties of Co–Zn ferrites, Journal of Magnetism and Magnetic Materials, vol. 257, pp. 296-305, 2003.