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http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/40255完整後設資料紀錄
| DC 欄位 | 值 | 語言 |
|---|---|---|
| dc.contributor.advisor | 胡崇德(Chong-Der Hu) | |
| dc.contributor.author | Hsin-Chieh Yang | en |
| dc.contributor.author | 楊欣潔 | zh_TW |
| dc.date.accessioned | 2021-06-14T16:43:28Z | - |
| dc.date.available | 2013-08-04 | |
| dc.date.copyright | 2008-08-04 | |
| dc.date.issued | 2008 | |
| dc.date.submitted | 2008-08-01 | |
| dc.identifier.citation | 1. G. T. Rado, Phys. Rev. Lett. 13, 335 (1964).
2. T. Goto, T. Kimura, G. Lawes, A. P. Ramirez, and Y. Tokura, Phys. Rev. Lett. 92, 257201 (2004). 3. L. C. Chapon et al., Phys. Rev. Lett. 93, 177402 (2004). 4. A. Yoshimori, J. Phys. Soc. Jpn. 14, 807 (1959) and J. Villain, J. Phys. Chem. Solids 11, 303 (1959). 5. A. V. Chubukov, J. Phys. C 21, L441 (1988). 6. H. Tanaka et al., J. Phys. Soc. Jpn. 57, 3979 (1988) and H. Tanaka, et al., J. Phys. Soc. Jpn. 58, 2930 (1989). 7. L. D. Landau and E. M. Lifshitz, Statistical Physics, (Pergamon Press, Oxford 1959). 8. M. Kenzelmann, A. B. Harris, S. Jonas, C. Broholm, J. Schefer, S. B. Kim, C. L. Zhang, S.–W. Cheong, O. P. Vajk, and J. W. Lynn, Phys. Rev. Lett. 95, 087206 (2005). 9. M. Mostovoy, Phys. Rev. Lett. 96, 067601 (2006). 10. T. Kimura, G. Laws, T. Goto, Y. Tokura, and A. P. Ramirez, Phys. Rev. B 71, 224425 (2005). 11. T. Kimura, T. Goto, H. Shintani, K. Ishizaka, T. Arima, and Y. Tokura, Nature (London) 426, 55 (2003). | |
| dc.identifier.uri | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/40255 | - |
| dc.description.abstract | 在本文中，我們提出一個模型來描述磁化強度及自由能在外加磁場前、後的行為，藉由以對稱性為基礎的藍道理論推衍出該自由能的形式。我們的機制顯示出外加場不僅能降低系統能量，並且會在外加場方向誘導出一均勻的磁化強度。此外，當外加場達到某一臨界值，在該方向原本與位置相關的磁化強度將會消失，並使得自由能轉變為另一種形式，使得整體系統的平衡能量更為減低。此模型對於預測外加磁場後磁化強度的變化將是相當有助益的。 | zh_TW |
| dc.description.abstract | In this thesis, we present a phenomenological model to describe the behavior of magnetization and free energy with and without the participation of an external field. The derivation of the free energy is developed in the frame of Landau theory based on symmetry requirements. Our mechanism demonstrates that the external field can not only decrease the free energy but induce the emergence of the uniform magnetization in the same direction of the external field. In addition, when the external field enhances to a critical value, the original spiral component vanishes and the formation of the free energy changes into another form that can decrease the energy much more. This model would be useful to predict how the magnetization affected by an external field. | en |
| dc.description.provenance | Made available in DSpace on 2021-06-14T16:43:28Z (GMT). No. of bitstreams: 1 ntu-97-R91222010-1.pdf: 537963 bytes, checksum: 0b0c0e8b90262f3b8bc27dba44f0f2d1 (MD5) Previous issue date: 2008 | en |
| dc.description.tableofcontents | Contents
Chapter 1 Introduction………………………………..……...………1 1-1 Multiferroics……………………....…………………...….…. ………….…..…...1 1-2 Ginzburg – Landau theory…………………...…………………………....…..…..2 Chapter 2 Theoreticalbackground……………………………….…..4 2-1 Landau theory………………………………………………………………….….4 2-1-1 Second order phase transitions ……………………………………...….…..4 2-1-2 Effect of external field………………………………………………………8 2-2Ginzburg-Landautheory………………………..…………………………………10 2-3 Symmetry considerations……………………...…………………………………11 2-3-1 Space groups……………………………..…………………………..…….11 2-3-2 Irreducible representation…………………..……………………..……….11 2-3-3 Symmetry and phase transition……………….……………………………12 Chapter 3 Analysis………..………..………..………..…………..………..…19 3-1Introduction……………………………………………………..……………..…19 3-2 The condition without external fields…………………………………………....20 3-3 Effect of external fields…………………………………………………………..23 3-3-1 Application of an external field along the y-axis…………………………..23 3-3-2 Application of an external field along the x-axis…………………………..26 3-3-3 Application of an external field along the z-axis…………………….…….29 Chapter 4 Calculations and results……...…………….……..………...…34 4-1 Discussions on theoreticalcalculation…………….……….…..………..34 4-1-1 Effect of an external field in y-axis……………………………….…….…34 4-1-2 Effect of an external field in x-axis……………………………….…….…35 4-1-3 Effect of an external field in z-axis……………………………..……….…36 4-2 Conclusion……………………………………………………..……..……......36 Reference………………………………45 | |
| dc.language.iso | en | |
| dc.subject | 多鐵性材料 | zh_TW |
| dc.subject | 外加場 | zh_TW |
| dc.subject | 藍道 | zh_TW |
| dc.subject | 對稱性 | zh_TW |
| dc.subject | 自由能 | zh_TW |
| dc.subject | External field | en |
| dc.subject | Symmetry | en |
| dc.subject | Free energy | en |
| dc.subject | Multiferroics | en |
| dc.subject | Landau | en |
| dc.title | 多鐵性材料之金茲伯格-藍道理論 | zh_TW |
| dc.title | Ginzburg-Landau theory of multiferroics | en |
| dc.type | Thesis | |
| dc.date.schoolyear | 96-2 | |
| dc.description.degree | 碩士 | |
| dc.contributor.oralexamcommittee | 郭光宇(Guang-Yu Guo),高英哲(Ying-Jer Kao) | |
| dc.subject.keyword | 自由能,藍道,多鐵性材料,外加場,對稱性, | zh_TW |
| dc.subject.keyword | Free energy,Landau,Multiferroics,External field,Symmetry, | en |
| dc.relation.page | 46 | |
| dc.rights.note | 有償授權 | |
| dc.date.accepted | 2008-08-01 | |
| dc.contributor.author-college | 理學院 | zh_TW |
| dc.contributor.author-dept | 物理研究所 | zh_TW |
| 顯示於系所單位： | 物理學系 | |
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