臺灣博碩士論文加值系統

我們研究不同結構的多鐵性材料YMnO3薄膜之光譜性質，分別以YSZ基板製成的六角晶系結構與SrTiO3基板製成的正交晶系結構，並探討在光譜上是否可以觀察得到磁電耦合的存在。
首先，比較基板與薄膜樣品的室溫光譜，我們觀察到六角晶系與正交晶系YMnO3薄膜在遠紅外光區皆有數個聲子吸收峰，可分別對應於[Phys. Rev. B 56, 2488 (1997)]及[Physica B 262, 1 (1999)]的第一原理計算結果，在近紅外至紫外光區的吸收峰，六角晶系YMnO3薄膜在1.6、2.4及5 eV，正交晶系YMnO3薄膜在5 eV，顯示著有電子能階躍遷的貢獻，由此印證了YMnO3薄膜在不同的基板下製備會形成不同的結構，同時也會展現各自的光譜性質及物理意義。
其次，我們研究這些樣品的變溫光譜響應，隨著溫度降低，六角晶系YMnO3薄膜在156、202及595 cm-1與正交晶系YMnO3薄膜在584 cm-1的振動模因為熱效應的緣故，頻率位置出現藍移現象且半高寬變窄；正交晶系YMnO3薄膜在450 cm-1處，隨溫度降低有下陷的趨勢，這是由於SrTiO3基板的結構相轉變所致；六角晶系YMnO3薄膜在高頻1.7 eV處，接近相變溫度時，頻率位置之斜率變化較陡峭，此現象可能與錳離子間磁矩之超交換相互作用效應有關。

We report the optical properties of multiferroic YMnO3 thin films. Single-crystalline YMnO3 thin films were grown on YSZ in a hexagonal structure and on SrTiO3 substrates in an orthorhombic structure. Our goal is to investigate the couplings of lattice, electronic, and magnetic structures of these materials.
The room-temperature infrared spectra of hexagonal and orthorhombic YMnO3 thin films are consistent with the results of first- principles calculations [Phys. Rev. B 56, 2488 (1997)] and [Physica B 262, 1 (1999)]. At higher frequencies, three optical excitations are observed at about 1.6, 2.4, and 5 eV in hexagonal YMnO3 thin film, while an interband transition appears at about 5 eV in orthorhombic YMnO3. This is mainly due to the fact that different substrates induce different crystal structures of YMnO3, and moreover influence their electronic structures.
With decreasing temperature, phonon modes at about 156、202 and 595 cm-1 in hexagonal YMnO3 thin film and 584 cm-1 in orthorhombic YMnO3 exhibit blue shift in positions and narrower linewidths. We also notice that a dip appears in the reflectivity at around 450 cm-1 to ascribe the cubic-to-tetragonal phase transition in the SrTiO3 substrate. Near the antiferromagnetic phase transition temperature, the slope of temperature-dependent frequency of 1.7 eV peak becomes sharper in hexagonal YMnO3 thin film, which may be associated with Mn-Mn superexchange interactions.

致謝 ……………………………………………………………… i
中文摘要 ………………………………………………………… ii
英文摘要 ………………………………………………………… iii
目錄 ……………………………………………………………… iv
表目錄 …………………………………………………………… vi
圖目錄 …………………………………………………………… viii

第一章 緒論 ……………………………………………………… 1
第二章 研究背景 ……………………………………………… 7
2-1 磁電性材料 …………………………………………… 7
2-2 多鐵特性-RMnO3 ……………………………………… 10
第三章 實驗儀器設備及其基本原理 ………………………… 17
3-1 傅立葉轉換紅外線光譜儀 …………………………… 17
3-2 光柵式分光儀 ………………………………………… 19
3-3 光譜分析原理介紹 …………………………………… 22
第四章 實驗樣品特性 ………………………………………… 39
4-1 樣品製成 ……………………………………………… 39
4-2 樣品結構 ……………………………………………… 39
4-3 磁性量測 ……………………………………………… 42
第五章 實驗結果與討論 ………………………………………… 52
5-1 YSZ與SrTiO3基板 …………………………………… 52
5-2六角晶系YMnO3薄膜 ………………………………… 55
5-3 正交晶系YMnO3薄膜 ………………………………… 62
5-4 計算分析 ……………………………………………… 66
第六章 結論與未來展望 ………………………………………… 128
參考文獻 ………………………………………………………… 132

[1] F. Pockels, “On the effect of an electrostatic field on the optical behavior of piezoelectric crystal”, Abh. Gott 39, 1 (1894).
[2] J. Valasek, “Piezoelectric and allied phenomena in Rochelle salt”, Phys. Rev. 15, 537 (1920).
[3] G. Bush and P. Scherrer, “Kurze Originalmitteilungen”, Naturwissenschaften 23, 737 (1935).
[4] N. A. Hill, “Why are there so few magnetic ferroelectrics”, J. Phys. Chem. B 104, 6694 (2000).
[5] C. Degenhardt, M. Fiebig, D. Frohlich, Th. Lottermoser, and R.V. Pisarev, “Nonlinear optical spectroscopy of electronic transitions in hexagonal manganites”, Appl. Phys. B 73, 139 (2001).
[6] M. Bibes and A. Barthelemy, “Towards a magnetoelectric memory”, Nature materials 7, 425 (2008).
[7] http://en.wikipedia.org/wiki/Pockels_cell
[8] M. N. Baibich, J. M. Broto, A. Fert, F. Nguyen Van Dau, F. Petroff, P. Eitenne, G. Creuzet, A. Friederich, and J. Chazelas, “Giant magnetoresistance of (001)Fe/(001)Cr magnetic superlattices”, Phys. Rev. Lett. 61, 2472 (1988).
[9] T. Kimura1, T. Goto, H. Shintani, K. Ishizaka, T. Arima, and Y. Tokura, “Magnetic control of ferroelectric polarization”, Nature 426, 55 (2003).
[10] N. Hur, S. Park, P. A. Sharma, J. S. Ahn, S. Guha, and S. W. Cheong, “Electric polarization reversal and memory in a multiferroic material induced by magnetic fields”, Nature 429, 392 (2004).
[11] W. Eerenstein, N. D. Mathur, and J. F. Scott, “Multiferroic and magnetoelectric materials”, Nature 442, 759 (2006).
[12] http://zh.wikipedia.org/w/index.php
[13] W. Prellier, M. P. Singh, and P. Murugavel, “The single-phase multiferroic oxides: from bulk to thin film”, J. Phys.: Condens. Matter 17, 803 (2005).
[14] C. Y. Ren, “Atomic, electronic, and ferroelectric properties of manganite RMnO3 (R=Ho,Er,Tm,Lu) in hexagonal and orthorhombic phases”, Phys. Rev. B 79, 125113 (2009).
[15] J. S. Zhou and J. B. Goodenough, “Unusual evolution of the magnetic interactions versus structural distortions in RMnO3 perovskites”, Phys. Rev. Lett. 96, 247202 (2006).
[16] A. Munoz, J. A. Alonso, M. T. Casais, M. J. Martinez-Lope, J. L. Martinez, and M. T. Fernandez-Diaz, “The magnetic structure of YMnO3 perovskite revisited”, J. Phys.: Condens. Matter 14, 3285 (2002).
[17] T. H. Lin, C. C. Hsieh, H. C. Shih, C. W. Luo, T. M. Uen, K. H. Wu, J. Y. Juang, J. Y. Lin, C. H. Hsu, and S. J. Liu, “Anomalous magnetic ordering in b-axis-oriented orthorhombic HoMnO3 thin films”, Appl. Phys. Lett. 92, 132503 (2008).
[18] N. Fujimura, T. Ishida, T. Yoshimura, and T. Ito, “Epitaxially grown YMnO3 film: New candidate for nonvolatile memory devices”, Appl. Phys. Lett. 69, 1011 (1996).
[19] H. L. Yakel Jnr, W. C. Koehler, E. F. Bertaut, and E. F. Forrat, “On the crystal structure of the manganese(III) trioxides of the heavy lanthanides and yttrium”, Acta Crystallogr. 16, 957 (1963).
[20] M. N. Iliev, H. G. Lee, V. N. Popov, M. V. Abrashev, A. Hamed, R. L. Meng, and C. W. Chu, “Raman- and infrared-avtive phonons in hexagonal YMnO3: Experiment and lattice-dynamical calculations’’, Phys. Rev. B 56, 2488 (1997).
[21] B. B. Van Aken, T. T. M. Palstra, A. Filippetti, and N. A. Spaldin, “The origin of ferroelectricity in magnetoelectric YMnO3”, Nature materials 3, 164 (2004).
[22] Z. J. Huang, Y. Cao, Y. Y. Sun, Y. Y. Xue, and C. W. Chu, “Coupling between the ferroelectric and antiferromagnetic orders in YMnO3”, Phys. Rev. B 56, 2623 (1997).
[23] T. Lottermoser, T. Lonkai, U. Amann, D. Hohlwein, J. Ihringer, and M. Fiebig, “Magnetic phase control by an electric field”, Nature. 430, 541 (2004).
[24] T. Katsufuji, S. Mori, M. Masaki, Y. Moritomo, N. Yamamoto, and H. Takagi, “Dielectric and magnetic anomalies and spin frustration in hexagonal RMnO3 (R=Y, Yb, and Lu)”, Phys. Rev. B 64, 104419 (2001).
[25] B. Lorenz, Y. Q. Wang, Y. Y. Sun, and C. W. Chu, “Large magnetodielectric effects in orthorhombic HoMnO3 and YMnO3”, Phys. Rev. B 70, 212412 (2004).
[26] J. Kim, S. Jung, M. S. Park, S. I. Lee, H. D. Drew, H. Cheong, K. H. Kim, and E. J. Choi, “Infrared signature of ion displacement in the noncollinear spin state of orthorhombic YMnO3” Phys. Rev. B 74, 052406 (2006).
[27] I. S. Smirnova, “Normal modes of the LaMnO3 Pnma phase: comparison with La2CuO4 Cmca phase’’, Physica B 262, 247 (1998).
[28] N. Hur, S. Park, P. A. Sharma, J. S. Ahn, S. Guha, and S. W. Cheong, “Electric polarization reversal and memory in a multiferroic material induced by magnetic fields”, Nature 429, 392 (2004).
[29] J. Cao, L. I. Vergara, J. L. Musfeldt, A. P. Litvinchuk, Y. J. Wang, S. Park, and S. W. Cheong, “Magnetoelastic coupling in DyMn2O5 via infrared spectroscopy”, Phys. Rev. B 78, 064307 (2008).
[30] C. Lucas, I. Eiroa, M. R. Nunes, P. A. Russo, M. M. L. Ribeiro Carrott, M. I. da Silva Pereira, and M. E. Melo Jorge, “Preparation and characterization of Ca1−xCexMnO3 perovskite electrodes”, J Solid State Electrochem 13, 943 (2009).
[31] 翁士民，高溫超導銅氧化物Y1-xCaxBa2Cu3Oy和Y1-xPrxBa2Cu4O8 之光譜研究，國立臺灣師範大學物理研究所碩士論文，93年6月。
[32] Douglas A. Skoog and James J. Leary著，林敬二、林宗義審譯，儀器分析，美亞書版股份有限公司，1971第四版上冊。
[33] A. Zibold, H. L. Liu, S. W. Moore, J. M. Graybeal, and D. B. Tanner, “Optical properties of single-crystl Sr2CuO2Cl2”, Phys. Rev. B 53, 11734 (1995).
[34] 謝志昌，基板穩定之六方與正交結構多鐵性稀土元素錳氧化物薄膜的磁與電子特性研究，國立交通大學電子物理系莊振益教授實驗室。
[35] M. N. Iliev, M. V. Abrashev, H. G. Lee, V. N. Popov, Y. Y. Sun, C. Thomsen, R. L. Meng, and C. W. Chu, “Raman spectroscpy of orthorhombic perovskitelike YMnO3 and LaMnO3’’‚ Phys. Rev. B 57, 2872 (1998).
[36] C. C. Hsieh, T. H. Lin, H. C. Shih, C. H. Hsu, C. W. Luo, J. Y. Lin, K. H. Wu, T. M. Uen, and J. Y. Juang, “Magnetic ordering anisotropy in orthorhombic multiferroic YMnO3 films’’‚ J. Appl. Phys. 104, 103912 (2008).
[37] J. Dho, C. W. Leung, J. L. MacManus-Driscoll, and M. G. Blamire, “Epitaxial and oriented YMnO3 film growth by pulsed laser deposition’’‚ Journal of Crystal Growth 267, 548 (2004).
[38] X. Marti, F. Sanchez, V. Skumryev, V. Laukhin, C. Ferrater, M. V. Garcia-Cuenca, M. Varela, and J. Fontcuberta, “Crystal texture selection in epitaxies of orthorhombic antiferromagnetic YMnO3 films’’‚ Thin Solid Films 516, 4899 (2008).
[39] A. V. Boris, N. N. Kovaleva, A. V. Bazhenov, A. V. Samoilov, N. C. Yeh, and R. P. Vasquez, “Infrared optical properties of La0.7Ca0.3MnO3 exitaxial films”, J. Appl. Phys. 81, 8 (1997).
[40] K. Kamaras, K. L. Barth, F. Keilmann, R. Henn, M. Reedyk, C. Thomsen, M. Cardona, J. Kircher, P. L. Richards, and J. L. Stehle, “The low-temperature infrared optical functions of SrTiO3 determined by reflectance spectroscopy and spectroscopic ellipsometry’’, J. Appl. Phys. 78, 2 (1995).
[41] M. Chen, D. B. Tanner, and J. C. Nino, “Infrared study of the phonon modes in bismuth pyrochlores’’, Phys. Rev. B 72, 054303 (2005).
[42] W. S. Choi, Soon Jae Moon, S. S. A. Seo, D. Lee, J. H. Lee, P. Murugavel, T. W. Noh, and Y. S. Lee, “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).
[43] W. S. Choi, D. G. Kim, S. S. A. Seo, S. J. Moon, D. Lee, J. H. Lee, H. S. Lee, D. Y. Cho, Y. S. Lee, P. Murugavel, J. Yu, and T. W. Noh, “Electronic structures of hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films: Optical spectroscopy and first-principles calculation’’, Phys. Rev. B 77, 045137 (2008).
[44] A. M. Kalashnikova and R. V. Pisarev, “Electronic structure of hexagonal rare-earth manganites RMnO3’’, JEPT Lett. 78, 143 (2003).
[45] Y. Tokura and N. Nagaosa, “Orbital physics in transition-metal oxides”, Science. 228, 462 (2000).
[46] K. C. Liang, H. L. Liu, H. D. Yang, W. N. Mei, and D. C. Ling, “Structural and optical studies of high dielectric constant (Na0.5A0.5)Cu3Ti4O12 (A = La and Bi)”, J. Phys.: Condens. Matter 20, 275238 (2008).
[47] A. B. Souchkov, J. R. Simpson, M. Quijada, H. Ishibashi, N. Hur, J. S. Ahn, S. W. Cheong, A. J. Millis, and H. D. Drew, “Exchange interaction effects on theoptical properties of LuMnO3’’‚ Phys. Rev. Let. 91, 027203 (2003).
[48] H. C. Gupta and P. Ashdhir, “Lattice dynamics of orthorhomic perovskite YMnO3’’, Physica B 262, 1 (1999).
[49] 何金龍，錳氧化物、含鋰的鈦氧化物及磁熱材料的光譜與結構性質研究，國立臺灣師範大學物理研究所博士論文，94年10月。
[50] L. Moreira, P. S. M. Lobo, G. Subodh, T. Sebastian, M. Matinaga, and A. Dias, “Optical phonon modes and dielectric behavior of Sr1-3x/2CexTiO3 microwave ceramics’’, Chem. Mater. 19, 6548 (2007).
[51] J. C. Galzerani and R. S. Katiyar, “The infrared reflectivity in SrTiO3 and the antidistortive transition’’, Solid State Commun. 41, 515 (1982).
[52] S. Z. Li, Z. B. Yan, T. Wei, S. J. Luo, B. Liu, K. F. Wang, and J. M. Liu, “Preparation of epitaxial orthorhombic YMnO3 thin films and the current-voltage rectifying effect’’ ‚ Appl. Phys. A 94, 975 (2008).
[53] J. F. Scott, “Raman spectra and lattice dynamics of -Berlinite (AlPO4)”, Phys. Rev. B 4, 1360 (1971).
[54] M. Zaghrioui, V. T. Phuoc, R. A. Souza, and M. Gervais, “Polarized reflectivity and lattice dynamics calculation of multiferroic YMnO3”, Phys. Rev. B 78, 184305 (2008).
[55] R. C. Rai, J. Cao, J. L. Musfeldt, S. B. Kim, S. W. Cheong, and X, Wei, “Spin-charge coupling and the high-energy magnetodielectric effic in hexagonal HoMnO3”, Phys. Rev. B 75, 184414 (2007).
[56] D. G. Tomuta, S. Ramakrishnan, G. J. Nieuwenhuys, and J. A. Mydosh, “The magnetic susceptibility, specific heat and dielectric constant of hexagonal YMnO3, LuMnO3 and ScMnO3”, J. Phys.: Condens. Matter 13, 4543 (2001).
[57] P. A. Sharma, J. S. Ahn, N. Hur, S. Park, S. B. Kim, S. Lee, J. G. Park, S. Guha, and S. W. Cheong, “Thermal conductivity of geometrically frustrated, ferroelectric YMnO3: Extraordinary spin-phonon interactions”, Phys. Rev. Lett. 93, 177202 (2004).
[58] D. Lee, J. H. Lee, P. Murugavel, S. Y. Jang, T. W. Noh, Y. Jo, M. H. Jung, Y. D. Ko, and J. S. Chung, “Epitaxial stabilization of artificial hexagonal GdMnO3 thin films and their magnetic properties”, Phys. Rev. Lett. 90, 182504 (2007).
[59] A. Veres, J. G. Noudem, S. Fourrez, and G. Bailleul, “The influence of iron substitution to manganese on the physical properties of YMnO3”, Solid State Sciences 8, 137 (2006).
[60] W. R. Chen, F. C. Zhang, J. Miao, B. Xu, X. L. Dong, L. X. Cao, X. G. Qiu, B. R. Zhao, and P. Dai, “Re-entrant spin glass behavior in Mn-rich YMnO3”, Appl. Phys. Lett. 87, 042508 (2005).
[61] A. Paolone, P. Roy, A. Pimenov, A. Loidl, O. K. Melnikov, and A. Ya. Shapiro “Infrared phonon spectrum of pure and doped LaMnO3”, Phys. Rev. B 61, 11255 (2000).
[62] Y. Takahashi, N. Kida, Y. Yamasaki, J. Fujioka, T. Arima, R. Shimano, S. Miyahara, M. Mochizuki, N. Furukawa, and Y. Tokura “Evidence for an electric-dipole active continuum band of spin excitations in multiferroic TbMnO3”, Phys. Rev. Lett. 101, 187201 (2008).
[63] 吳宗展，龐磁阻磁穿隧之研究，國立中山大學物理研究所碩士論文，91年10月。
[64] http://www.webelements.com/
[65] J. Rodriguez-Carvajal, M. Hennion, F. Moussa, and A. H. Moudden, “Neutron-diffraction study of the Jahn-Teller transition in stoichiometric LaMnO3”, Phys. Rev. B 57, R3189 (1998).