臺灣博碩士論文加值系統

科學家Skyrme在1961年在理論上預測了一種粒子，描述在局部空間中，形成一個自旋結構特殊狀態，稱為Skyrmion。它屬於非對稱型的自旋拓樸結構。直到最近十年，固態物理科學家利用缺乏空間對稱性的晶體結構磁性塊材材料，其中的自旋軌道耦合所產生的Dzyaloshinskii-Moriya interaction(DMI)，觀察到了Skyrmion的存在。磁性材料薄膜與其他材料的介面同樣具有空間對稱性的破壞與DMI。因此在磁性微米與奈米結構中，Skyrmion的形成與操控，成為資訊儲存或是邏輯運算的有趣課題。
我們以實驗和數值模擬的方式研究具有垂直異向性的磁性薄膜材料中，如何形成與觀察Skyrmion。第一部份利用OOMMF軟體對磁盤做模擬，探討形成skyrmion所需要的條件，我們改變不同尺寸大小以及改變交流磁場在磁性薄膜水平方向的振幅大小。不同材料介面上，因為自旋軌道耦合較強的材料可以引起較強的DMI，此交互作用力大小是決定Skyrmion是否穩定存在的重要原因。
第二部分，我們透過Kerr image觀測在多層膜的磁區壁翻轉過程，用以決定DMI的大小。樣品分為兩種，第一種為Co/Pd多層膜上面覆蓋Ta，第二種為上下兩層Ta中間夾Co/Pd多層膜。透過分析，可以獲得磁區壁的移動速度，計算出DMI的能量與數值。
第三部分，我們利用Scanning Kerr microscopy觀測在微米尺寸樣品中磁區翻轉過程，透過此光學量測，我們要確認此系統空間與時間解析度，在微米或奈米等級的尺寸下，觀測skyrmion的能力。

致謝 i
摘要 ii
Abstract iii
目錄 v
圖目錄 vii
表目錄 xii
第一章 緒論 1
第二章 基礎理論 6
2-1 磁性物質簡介 6
2-1-1 鐵磁性(Ferromagnetism) 6
2-1-2 反鐵磁性 (Antiferromagnetism) 7
2-1-3 順磁性 (paramagnetism) 8
2-1-4 抗磁性 (Diamagnetism) 9
2-1-5 亞鐵磁性 (Ferrimagnetism) 9
2-2 磁異向性（Magnetic anisotropy） 10
2-2-1 磁晶格異向性(Magneto crystalline anisotropy) 10
2-2-2 形狀異向性 (Shape magnetic anisotropy) 12
2-2-3 垂直異向性 (Perpendicular magnetic anisotropy) 12
2-3 霍爾效應 (Hall effect) 14
2-4 異常霍爾效應 (Anomalous Hall effect) 14
2-5 DMI (Dzyaloshinskii-Moriya interaction) 15
2-6 Skyrmion 16
第三章 文獻回顧 19
3-1 Kerr-image 19
3-2 Skyrmion 23
3-3 DMI的計算方法 26
第四章 實驗流程與儀器原理 28
4-1 濺鍍系統 28
4-2 四點量測 30
4-3 磁光柯爾量測系統(MOKE system) 33
4-4交變梯度磁力計(AGM) 37
4-5 模擬軟體 38
第五章 結果與討論 40
5-1 磁盤模擬 40
5-2 Kerr image討論以及計算DMI方法 109
5-3 Scanning Kerr microscope之觀測 118
第六章 結論 124
參考文獻 125

[1]S. Chikazumi, Physics of Ferromagnetism, Clarendon Press, (1997)
[2]P. F. Garcia, A. D. Meinhaldt, and A. Suna, Appl. Phys. Lett. 47,178 (1985)
[3]M. N. Baibich, J. M. Broto, A. Fert, F. Nguyen Van Dau, F. Petroff, P. Etienne, G. Creuzet, A. Friederich, and J. Chazelas Phys. Rev. Lett. 61, 2472 (1988)
[4]Bridgman, P. W. (1939). Biographical Memoir of Edwin Herbert Hall. National Academy of Sciences.
[5]J. Kerr, Philos. Mag. 3, 339 (1877); 5, 161 (1878)
[6]E. R. Moog and S. D. Bader, Superlattices Microstruct. 1, 543 (1985) ;
[7]S. D. Bader, E. R. Moog, and P. Gruぴnberg, J. Magn. Magn. Mater. 53, L295 (1986)
[8]Z. Q. Qiu , S. D. Bader , Review of Scientific Instruments 71, 1243 (2000)
[9]Dzyaloshinskii, I. E. Thermodynamic theory of weak ferromagnetism in antiferromagnetic substances. Sov. Phys. JETP 5, 1259–1262 (1957)
[10]Moriya, T. Anisotropic superexchange interaction and weak ferromagnetism. Phys. Rev. 120, 91–98 (1960)
[11]Miron, I. M. et al. Current-driven spin torque induced by the Rashba effect in a ferromagnetic metal layer. Nature Mater. 9, 230–234 (2010)
[12]A Non-Linear Field Theory. T. H. R. Skyrme The royal society 1961.DOI: 10.1098/rspa.1961.0018
[13]Emilie Jué, C. K. Safeer, Marc Drouard, Alexandre Lopez, Paul Balint, Nature Material, DOI: 10.1038/NMAT4518
[14]Liliana Buda-Prejbeanu1,2,3, Olivier Boulle1,2,3, Stephane Auret1,2,3, Alain Schuhl4,
[15]Aurelien Manchon, Ioan Mihai Miron and Gilles Gaudin, Nature Materials 15, 272–277 (2016)
[16]Parkin, S. S. P., Hayashi, M. & Thomas, L. Magnetic domain-wall racetrack memory. Science 320, 190–194 (2008)
[17]Bram van Dijk, Skyrmions and the Dzyaloshinskii-Moriya Interaction,
[18]Gilbert, T. L. A phenomenological theory of damping in ferromagnetic materials. Magn. IEEE Trans. 40, 3443–3449 (2004)
[19]Wanjun Jiang, Pramey Upadhyaya, Wei Zhang, Guoqiang Yu,M . Benjamin Jungfleisch, Frank Y. Fradin, John E. Pearson, Yaroslav Tserkovnyak, Kang L. Wang, Olle Heinonen, Suzanne G. E. te Velthuis, Axel Hoffmann, AAAS Vol. 349, Issue 6245, pp. 283-286
[20]Massimiliano d’Aquino, Nonlinear Magnetization Dynamics in Thin-film and Nanoparticles, Ph.D. thesis, Naples Italy: University of Naples Federico II, 2004.
[21]Albert Fert, Vincent Cros and João Sampaio , Nature Nanotechnology 8, 152–156 (2013)
[22]Evidence for stable room-temperature skyrmions, https://phys.org/news/2015-07-evidence-stable-room-temperature-skyrmions.html
[23]Karin Everschor-Sitte and Matthias Sitte, DOI: 10.1063/1.4870695
[24]Gorchon, J. et al. Pinning-dependent field-driven domain wall dynamics and thermal scaling in an ultrathin Pt/Co/Pt magnetic film. Phys. Rev. Lett. 113, 027205 (2014)
[25]S. Sugimoto, Y. Fukuma, S. Kasai, T. Kimura, A. Barman, and Y. C. Otani, Phys. Rev. Lett. 106, 197203 (2011)
[26]S. Mühlbauer, B. Binz, F. Jonietz, C. Pfleiderer, A. Rosch, A. Neubauer, R. Georgii, P. Böni, AAAS Vol. 323, Issue 5916, pp. 915-919
[27]X.Z. Yu, N. Kanazawa, W.Z. Zhang, T. Nagai, T. Hara, K. Kimoto, Y. Matsui, Y. Onose & Y. Tokura, Nature Communications 3, Article number: 988
[28]H. J, Mamin, D. Rugar, J. E, Stern, R E, Fontana, Jr.,a) and P. Kasiraj,Appl. Phys. Lett. 55, 318 (1989)
[29]A.Fassatoui, R.Belhi , J.Vogel , K.Abdelmoula, JMMM Vol. 420, p102-108 (2016)
[30]B.D. Cullity,Elements of X-ray Diffraction, A.W.Pub.Comp.Inc.,Boston,1978
[31]S. Ikeda, K. Miura, H. Yamamoto, K. Mizunuma , H. D. Gan , M. Endo , S. Kanai , J. Hayakawa , F. Matsukura and H. Ohno, Nature Materials 9, 721–724 (2010)
[32]C. J. Durrant and R. J. Hicken, Qiang Hao and Gang Xiao, PHYSICAL REVIEW B 93, 014414 (2016)
[33]S. X. Huang and C. L. Chien，PRL 108, 267201 (2012)
[34]R. Soucaille, M. Belmeguenai, J. Torrejon, J.-V. Kim, T. Devolder, Y. Roussign´e, S.-M. Ch´erif, PHYSICAL REVIEW B 94, 104431 (2016)
[35]A. A. Stashkevich,2,4 M. Hayashi,3 and J.-P. Adam
[36]NIST OOMMF software v.1.2a4, http://math.nist.gov/oommf/
[37]N. Nagaosa, J. Sinova, S. Onoda, A. H. MacDonald, and N. P. Ong, Rev. Mod. Phys. 82, 1539 (2010)
[38]JiaweiYu, XuepengQiu, YangWu, JungbumYoon, Praveen Deorani, Jean Mourad Besbas, Aurelien Manchon & HyunsooYang, Scientific Reports , srep32629
[39]zur Erlangung des Grades eines Doktors der Naturwissenschaften in der Fakultぴat fぴur Physik und Astronomie der Ruhr-Universitぴat Bochum, A scanning Kerr microscope with high spatial and temporal resolutions
[40]Yizhou Liu, Gen Yin, Jiadong Zang, Jing Shi, and Roger K. Lake, Applied Physics Letters 107, 152411 (2015)
[41]Yan Zhou & Motohiko Ezawa, DOI: 10.1038/ncomms5652
[42]Dustin A. Gilbert, Brian B. Maranville, Andrew L. Balk, Brian J. Kirby, Peter Fischer, Daniel T. Pierce, John Unguris, Julie A. Borchers & Kai Liu, DOI: 10.1038/ncomms9462
[43]Yuan Tian, Li Ye, and Xiaofeng Jin, DOI: 10.1103/PhysRevLett.103.087206
[44]SeonghoonWoo, Kai Litzius, Benjamin Krüger, Mi-Young Im, Lucas Caretta1, Kornel Richter, Maxwell Mann, Andrea Krone, Robert M. Reeve, MarkusWeigand, Parnika Agrawal, Ivan Lemesh, Mohamad-Assaad Mawass, Peter Fischer, Mathias Kläui and Georey S. D. Beach, DOI: 10.1038/NMAT4593
[45]Chao-Yao Yang, Shu-Jui Chang, Min-Han Lee, Kuei-Hung Shen, Shan-Yi Yang,Horng-Ji Lin & Yuan-Chieh Tseng, Scientific Report, DOI: 10.1038/srep17169
[46]Pin Ho, Jinshuo Zhang, David C. Bono, Jingsheng Chen, and Caroline A. Ross, IEEE, DOI: 10.1109/TMAG.2016.2526972
[47]Harald Oezelt, Eugenie Kirk, Phillip Wohlhüter, Elisabeth Müller, Laura Jane Heyderman, Alexander Kovacs, and Thomas Schrefl, AIP Advances 7, 056001 (2017); doi: 10.1063/1.4973295
[48]Luqiao Liu, Chi-Feng Pai, Y. Li, H. W. Tseng, D. C. Ralph, R. A. Buhrman, Science 336 (6081), 555-558, DOI: 10.1126/science.1218197
[49]Shujun Chen, Qiyuan Zhu, Senfu Zhang, Chendong Jin, Chengkun Song, Jianbo Wang and Qingfang Liu, J. Phys. D: Appl. Phys. 49 (2016) 195004
[50]Anjan Soumyanarayanan, Nicolas Reyren, Albert Fert & Christos Panagopoulos, doi:10.1038/nature19820
[51]G. Chen, J. Zhu,1 A. Quesada, J. Li, A. T. N’Diaye, Y. Huo, T. P. Ma, Y. Chen, H.Y. Kwon, C. Won, Z. Q. Qiu, A. K. Schmid, and Y. Z. Wu, PRL 110, 177204 (2013)
[52]Hongxin Yang, André Thiaville, Stanislas Rohart, Albert Fert, and Mairbek Chshiev, PRL 115, 267210 (2015)
[53]Ashis Kumar Nandy, Nikolai S. Kiselev, and Stefan Blügel, PRL 116, 177202 (2016)
[54]L. D. Geng and Y. M. Jin, EPL, 116 (2016) 36002, DOI: 10.1209/0295-5075/116/36002