簡易檢索 / 詳目顯示

研究生: 蔡育仁
Yu-Ren Cai
論文名稱: 菱形與類四方晶系結構鐵酸鉍薄膜之光譜性質研究
Optical studies of rhombohedral and tetragonal-like BiFeO3 thin films
指導教授: 劉祥麟
Liu, Hsiang-Lin
學位類別: 碩士
Master
系所名稱: 物理學系
Department of Physics
論文出版年: 2012
畢業學年度: 100
語文別: 中文
論文頁數: 132
中文關鍵詞: 鐵酸鉍吸收光譜拉曼光譜能隙自旋聲子耦合
英文關鍵詞: BiFeO3, absorption, Raman, energy gap, spin-phonon coupling
論文種類: 學術論文
相關次數: 點閱:115下載:4
分享至:
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報
  • 本論文研究多鐵材料 BiFeO3 薄膜 (厚度約為 30 nm) 成長於不同基板 (LSAT、DyScO3、LaAlO3) 的光譜響應。x 光繞射能譜顯示 BiFeO3 成長於 DyScO3 及 LSAT 基板上呈現菱形晶系結構,成長於 LaAlO3 基板上呈現類四方晶系結構。我們量測薄膜的穿透光譜,計算吸收係數,估算 BiFeO3 薄膜成長於 LSAT 與 LaAlO3 基板上室溫能隙值約為 2.58 eV 與 3.08 eV。隨著溫度下降,菱形晶系 BiFeO3 薄膜 (LSAT 基板) 能隙值在低於 100 K 時,明顯偏離理論預測值,此可能與 BiFeO3 塊材於低溫具自旋玻璃態以及晶格不匹配度改變有關。此外,菱形晶系 BiFeO3 薄膜樣品於 2.8 ~ 3.2 eV 與 4.0 ~ 4.4 eV 能量區間,與類四方晶系 BiFeO3 薄膜樣品於 3.45 ~ 3.5 eV 與 4.27 ~ 4.3 eV 能量區間,其振盪子權重分別在 200 K 與 150 K 附近顯現極值,此亦與 BiFeO3 薄膜樣品於 200 K 與 150 K 的自旋重新排列行為有關。
    其次,我們量測薄膜的高溫拉曼散射光譜,菱形晶系結構 BiFeO3 薄膜 (DyScO3 基板) 的 173 cm-1 拉曼峰於 600 K 附近展現不連續紅移現象,此與自旋聲子之交互作用有關,我們計算出自旋聲子耦合係數約為 12.9 mRy/Å2。另一方面,類四方晶系結構 BiFeO3 薄膜 (LaAlO3 基板) 在 360 K 附近,221 cm-1、269 cm-1、359 cm-1 及 586 cm-1 拉曼峰頻率位置與半高寬有階梯式的變化,造成此現象有兩種可能因素:(i) 類四方晶系結構從 MC-Type 轉換為 MA-Type;(ii) 反鐵磁有序相轉換。我們也觀察到 586 cm-1 與 685 cm-1 拉曼峰在接近 600 K 時有不連續紅移現象,此可能為接近尼爾溫度時,受到自旋聲子耦合交互作用影響所致。

    We report the optical properties of 30 nm-thick multiferroic BiFeO3 (BFO) thin films. The x-ray diffraction data indicate that BiFeO3 thin film is rhombohedral phase grown on LSAT and DSO substrates while is tetragonal-like phase on a LAO substrate.
    The absorption coefficient of these thin films determined from the transmission spectra shows the value of bandgap to be about 2.58 eV and 3.08 eV for BFO/LAST and BFO/LAO. Furthermore, the bandgap of BFO/LSAT deviates from the theoretical predictions in terms of Bose-Einstein model below 100 K that is likely associated with spin-glass phase observed in bulk BFO or misfit strain change between thin film and substrate at low temperatures. Additionally, the spectral weight of two oscillators in the energy range of 2.8 ~ 4.4 eV shows an extreme behavior at 200 K in BFO/LSAT and at 150 K in BFO/LAO. These anomalies could be related to spin-reorientation transition.
    Raman-active phonon mode observed near 173 cm-1 in BFO/LSAT exhibits a discontinuous redshift at about 600 K, indicating a spin-phonon interaction with a coupling constant of 12.9 mRy/Å2. On the other hand, the peak position and linewidth of the 221 cm-1, 269 cm-1, 359 cm-1, 586 cm-1, and 685 cm-1 phonon modes observed in BFO/LAO show a step-like change at about 360 K, which could arise from either the structural transformation between tetragonal-like Mc- and MA-type or antiferromagnetic ordering. Finally, the 586 cm-1 and 685 cm-1 phonon modes observed in BFO/LAO also exhibits a discontinuous redshift at about 600 K driven by a spin-phonon coupling.

    致謝 i 中文摘要 iii 英文摘要 v 目錄 vi 圖目錄 viii 表目錄 xv 第一章 緒論 1 第二章 研究背景 7 第三章 實驗儀器設備與其基本原理 28 3-1 光譜儀系統 28 3-2 光譜分析原理介紹 32 3-2-1 光譜分析原理介紹 32 3-2-2 拉曼散射原理 34 第四章 實驗樣品特性 41 4-1 樣品製程 41 4-2 樣品結構 41 第五章 實驗結果與討論 49 5-1 穿透光譜研究 49 5-2 拉曼散射光譜研究 57 第六章 結論與未來展望 108 參考文獻 111

    [1] J. Wang, J. B. Neaton, H. Zheng, V. Nagarajan, S. B. Ogale, B. Liu, D. Viehland, V. Vaithyanathan, D. G. Schlom, U. V. Waghmare, N. A. Spaldin, K. M. Rabe, M. Wuttig, and R. Ramesh, “Epitaxial BiFeO3 multiferroic thin film heterostructures”, Science 299, 1719 (2003).
    [2] R. J. Zeches, M. D. Rossell, J. X. Zhang, A. J. Hatt, Q. He, C. H. Yang, A. Kumar, C. H. Wang, A. Melville, C. Adamo, G. Sheng, Y. H. Chu, J. F. Ihlefeld, R. Erni, C. Ederer, V. Gopalan, L. Q. Chen, D. G. Schlom, N. A. Spaldin, L. W. Martin, and R. Ramesh, “A strain-driven morphotropic phase boundary in BiFeO3”, Science 326, 977 (2009).
    [3] K. Takahashi, N. Kida, and M. Tonouchi, “Terahertz radiation by an ultrafast spontaneous polarization modulation of multiferroic BiFeO3 thin films”, Phys. Rev. Lett. 96, 117402 (2006).
    [4] W. L. Chan, J. Deibel, and D. M Mittleman, “Imaging with terahertz radiation”, Rep. Prog. Phys. 70, 1325 (2007).
    [5] F. Gao, Y. Yuan, K. F. Wang, X. Y. Chen, F. Chen, and J. M. Liu, ”Preparation and photoabsorption characterization of BiFeO3 nanowires”, Appl. Phys. Lett. 89, 102506 (2006).
    [6] P. Hermet, M. Goffinet, J. Kreisel, and P. Ghosez, “Raman and infrared spectra of multiferroic bismuth ferrite from first principles”, Phys. Rev. B 75, 220102 (2007).
    [7] S. J. Clark and J. Robertson, “Band gap and Schottky barrier heights of multiferroic BiFeO3”, Appl. Phys. Lett. 90, 132903 (2007).
    [8] S. R. Basu, L. W. Martin, Y. H. Chu, M. Gajek, R. Ramesh, R. C. Tai, X. Xu, and J. L. Musfeldt, “Photoconductivity in BiFeO3 thin films”, Appl. Phys. Lett. 92, 091905 (2008).
    [9] M. K. Singh, R. S. Katiyar, and J. F. Scott, “New magnetic phase transitions in BiFeO3”, J. Phys.: Condens. Matter 20, 252203 (2008).
    [10] R. L. White, “Review of revent work on the magnetic and spectroscopic properties of the rare-earth orthoferrites”, J. Appl. Phys. 40, 1061 (1969).
    [11] M. K. Singh, W. Prellier, M. P. Singh, R. S. Katiyar, and J. F. Scott, “Spin-glass transition in single-crystal BiFeO3”, Phys. Rev. B 77, 144403 (2008).
    [12] J. Diouri, J. P. Lascaray, and M. El Amrani, “Effect of the magnetic order on the optical-absorption edge in Cd1-xMnxTe”, Phys. Rev. B 31, 7995 (1985).
    [13] M. K. Singh, S. Dussan, W. Prellier, and R. S. Katiyar, “One-magnon light scattering and spin-reorientation transition in epitaxial BiFeO3 thin films”, J. Magn. Magn. Mater. 321, 1706 (2009).
    [14] X. S. Xu, T. V. Brinzari, S. Lee, Y. H. Chu, L. W. Martin, A. Kumar, S. McGill, R. C. Rai, R. Ramesh, V. Gopalan, S. W. Cheong, and J. L. Musfeldt, “Optical properties and magnetochromism in multiferroic BiFeO3”, Phys. Rev. B 79, 134425 (2009).
    [15] V. Železný, D. Chvostová, L. Pajasová, I. Vrejoiu, and M. Alexe, “Optical properties of epitaxial BiFeO3 thin films”, Appl. Phys. A 100, 1217 (2010).
    [16] I. C. Infante, S. Lisenkov, B. Dupe, M. Bibes, S. Fusil, E. Jacquet, G. Geneste, S. Petit, A. Courtial, J. Juraszek, L. Bellaiche, A. Barthelemy, and B. Dkhil, “Bridging multiferroic phase transitions by epitaxial strain in BiFeO3”, Phys. Rev. Lett. 105, 057601 (2010).
    [17] M. N. Iliev, M. V. Abrashev, D. Mazumdar, V. Shelke, and A. Gupta, “Polarized Raman spectroscopy of nearly tetragonal BiFeO3 thin films”, Phys. Rev. B 82, 014107 (2010).
    [18] M. K. Singh and R. S. Katiyar, “Phonon anomalies near the magnetic phase transitions in BiFeO3 thin films with rhombohedral R3c symmetry”, J. Appl. Phys. 109, 07D916 (2011).
    [19] K. Y. Choi, S. H. Do, P. Lemmens, D. Wulferding, C. S. Woo, J. H. Lee, K. Chu, and C. H. Yang, “Anomalous low-energy phonons in nearly tetragonal BiFeO3 thin films”, Phys. Rev. B 84, 132408 (2011).
    [20] I. C. Infante, J. Juraszek, S. Fusil, B. Dupe, P. Gemeiner, O. Dieguez, F. Pailloux, S. Jouen, E. Jacquet, G. Geneste, J. Pacaud, J. Iniguez, L. Bellaiche, A. Barthelemy, B. Dkhil, and M. Bibes, “Multiferroic phase transition near room temperature in BiFeO3 films”, Phys. Rev. Lett. 107, 237601 (2011).
    [21] C. J. Cheng, C. Lu, Z. Chen, L. You, L. Chen, J. Wang, and T. Wu, “Thickness-dependent magnetism and spin-glass behaviors in compressively strained BiFeO3 thin films”, Appl. Phys. Lett. 98, 242502 (2011).
    [22] Y. Qi, Z. Chen, L. Wang, X. Han, J. Wang, T. Sritharan, and L. Chen, “Temperature-driven evolution of hierarchical nanodomain structure in tetragonal-like BiFeO3 films”, Appl. Phys. Lett. 100, 022908 (2012).
    [23] Z. Chen, S. Prosandeev, Z. L. Luo, Wei Ren, Y. Qi, C. W. Huang, Lu You, C. Gao, I. A. Kornev, T. Wu, J. Wang, P. Yang, T. Sritharan, L. Bellaiche, and L. Chen, “Coexistence of ferroelectric triclinic phases in highly strained BiFeO3 films”, Phys. Rev. B 84, 094116 (2011).
    [24] 鄧勃、寧永成、劉密新著,儀器分析,清華大學出版社出版,中華民國八十年五月第一版。
    [25] 王智弘 國立交通大學材料科學與工程學系碩士論文,民國 98 年。
    [26] W. S. Choi, S. J. Moon, S. S. A. Seo, D. Lee, J. H. Lee, P. Murugavel, and T. W. Noh, “Optical spectroscopic investigation on the coupling of electronic and magnetic structure in multiferroic hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films”, Phys. Rev. B 78, 054440 (2008).
    [27] S. Gomez-Salces, F. Aguado, F. Rodriguez, R. Valiente, J. Gonzalez, R. Haumont, and J. Kreisel, “Effect of pressure on the band gap and the local FeO6 environment in BiFeO3”, Phys. Rev. B 85, 144109 (2012).
    [28] P. Hannaford, “The oscillator strength in atomic absorption spectroscopy”, Microchemical journal 63, 43 (1999).
    [29] W. W. Li, J. J. Zhu, J. D. Wu, J. Gan, Z. G. Hu, M. Zhu, and J. H. Chu, “Temperature dependence of electronic transitions and optical properties in multiferroic BiFeO3 nanocrystalline film determined from transmittance spectra”, Appl. Phy. Lett. 97, 121102 (2010).
    [30] W. Baltensperger and J. S. Helman, “Influence of magnetic order in insulators on the optical phonon frequency”, Helv. Phys. Acta. 41, 668 (1968).
    [31] J. Lu, A. Gunther, F. Schrettle, F. Mayr, S. Krohns, P. Lunkenheimer, A. Pimenov, V. D. Travkin, A. A. Mukhin, and A. Loidl, “On the room temperature multiferroic BiFeO3: magnetic, dielectric and thermal properties”, Eur. Phys. J. B 75, 451 (2010).
    [32] S. Issing, A. Pimenov, V. Yu. Ivanov, A. A. Mukhin, and J. Geurts, “Composition-dependent spin-phonon coupling in mixed crystals of the multiferroic maganite Eu1-xYxMnO3 (0 < x < 0.5) studied by Raman spectroscopy”, Phys. Rev. B 81, 024304 (2010).
    [33] O. Dieguez, O. E. Gonzalez-Vazquez, J. C. Wojdeł, and J. Iniguez, “First-principles predictions of low-energy phases of multiferroic BiFeO3”, Phys. Rev. B 83, 094105 (2011).
    [34] J Kreisel, P Jadhav, O. Chaix-Pluchery, M. Varela, N. Dix, F. Sanchez, and J. Fontcuberta, “A phase transition close to room temperature in BiFeO3 thin films”, J. Phys.: Condens. Matter 23, 342202 (2011).
    [35] W. Siemons, M. D. Biegalski, J. H. Nam, and H. M. Christen, “Temperature-driven structural phase transition in tetragonal-like BiFeO3”, Appl. Phys. Express 4, 095801 (2011).
    [36] G. J. MacDougall, H. M. Christen, W. Siemons, M. D. Biegalski, J. L. Zarestky, S. Liang, E. Dagotto, and S. E. Nagler, “Antiferromagnetic transitions in tetragonal-like BiFeO3”, Phys. Rev. B 85, 100406 (2012).
    [37] O. Chaix-Pluchery and J. Kreisel, “Raman scattering of perovskite DyScO3 and GdScO3 single crystals”, J. Phys.: Condens. Matter 21, 175901 (2009).
    [38] H. Fukumura, H. Harima, K. Kisoda, M. Tamada, Y. Noguchi, and M. Miyayama, “Raman scattering study of multiferroic BiFeO3 single crystal”, J. Magn. Magn. Mater. 310, e367 (2007).
    [39] M. V. Abrashev, A. P. Litvinchuk, M. N. Iliev, and R. L. Meng, “Comparative study of optical phonons in the rhombohedrally distorted perovskites LaAlO3 and LaMnO3”, Phys. Rev. B 59, 4146 (1999).
    [40] M. K. Singh, H. M. Jang, S. Ryu, and M. H. Jo, “Polarized Raman scattering of multiferroic BiFeO3 epitaxial films with rhombohedral R3c symmetry”, Appl. Phys. Lett. 88, 042907 (2006).
    [41] D. Mazumdar, V. Shelke, M. Iliev, S. Jesse, A. Kumar, S. V. Kalinin, A. P. Baddorf, and A. Gupta, “Nanoscale switching characteristics of nearly tetragonal BiFeO3 thin films”, Nano Lett. 10, 2555 (2010).
    [42] S. A. Lourenc¸ I. F. L. Dias, J. L. Duarte, E. Laureto, E. A. Meneses, J. R. Leite, and I. Mazzaro, “Temperature dependence of optical transitions in AlGaAs”, J. Appl. Phys. 89, 6159 (2001).
    [43] A. Palewicz, I. Sosnowska, R. Przeniosło, and A. W. Hewat, “BiFeO3 crystal structure at low temperatures”, Acta. Phys. Pol. A 117, 296 (2010).
    [44] S. Kamba, V. Goian, M. Orlita, D. Nuzhnyy, J. H. Lee, D. G. Schlom, K. Z. Rushchanskii, M. Lezaic, T. Birol, C. J. Fennie, P. Gemeiner, B. Dkhil, V. Bovtun, M. Kempa, J. Hlinka, and J. Petzelt, “Magnetodielectric effect and phonon properties of compressively strained EuTiO3 thin films deposited on (001)(LaAlO3)0.29- (SrAl1/2Ta1/2O3)0.71”, Phys. Rev. B 59, 094435 (2012).
    [45] S. A. Hayward, S. A. T. Redfern, and E. K. H. Salje, “Order parameter saturation in LaAlO3”, J. Phys.: Condens. Matter 14, 10131 (2002).

    下載圖示
    QR CODE