中文摘要
自旋電子學，同時利用電子自旋與電荷的特性，在金屬氧化物半導體場效應晶體之後已經被廣泛地關注在未來元件應用上．鐵三矽為居禮溫度達840K的磁性金屬．由於鐵三矽與砷化鎵的晶格常數非常匹配，致使鐵三矽可以磊晶地成長在砷化鎵，並且擁有高結晶性以及原子級平整的介面．因此鐵三矽/砷化鎵異質結構成為研究自旋電子注入到砷化鎵最有可能的候選．
此論文中主要研究藉由分子束磊晶方式成長鐵三矽薄膜在砷化鎵(001)之樣品．從異向性磁阻量測中，我們的研究成果顯示當外加電流沿著鐵三矽的磁難軸時，隨著角度變化的磁阻表現出不尋常的鋸齒狀行為．然而當改變外加電流方向從沿著磁難軸到磁易軸時，隨著角度變化的磁阻表現出常規的異向性磁阻cos2(θM)行為．除此之外，磁光效應也被用來研究鐵三矽薄膜的磁異向性，並從實驗決定出異向常數K1與單軸異向性常數Ku．由K1/ Ku比值用來進一步解釋異向性磁阻之結果．
除了磁異向性之研究，我們也使用鐵三矽成為自旋電流來源研究自旋注入．自旋幫浦，藉由傳遞磁矩進動的自旋角動量給傳導電子而產生純自旋電流，被用來研究在覆蓋金屬（鉑與金）的磊晶鐵三矽薄膜與多晶鎳鐵合金薄膜．在由共振腔提供的微波與橫向磁場下，由於反自旋霍爾效應產生的電壓在鐵磁共振的情況中被量測到．從鎳鐵合金與鐵三矽的數據所推論出的鉑與金的自旋霍爾角度，與先前研究發表的數值吻合．
我們也展示在鐵三矽/砷化鎵異質結構下的自旋幫浦實驗．藉由調整砷化鎵過渡層的厚度與參雜程度，在磁性金屬/半導體異質結構下常見的加熱效應可以被有效消除．並在鐵三矽/p型砷化鎵觀察到49.2 μV左右的巨大的反自旋霍爾電壓．由於n型砷化鎵電阻率較小，大約小0.4倍的反自旋霍爾電壓在鐵三矽/n型砷化鎵被觀察到．藉由估算n型與p型砷化鎵的自旋擴散長度的最大值，最小的自旋霍爾角度分別估算為1.910-4 與2.810-5．

Abstract
Spintronics, which takes advantage of both the charge and spin of the electron property, has been paid much attention for further device application beyond the conventional metal-oxide-semiconductor field effect transistor. Fe3Si, a ferromagnetic metal with Curie temperature of 840K, can be epitaxially grown on GaAs with high crystallinity and atomically abrupt interface due to the small lattice mismatch. Hence, Fe3Si/GaAs heterostructure becomes a promising candidate to study the spin injection into GaAs.
In this dissertation, the study was focused on the epitaxial Fe3Si film grown on GaAs (001) by molecular beam epitaxy. From the anisotropic magnetoresistance measurement, our study showed that when a current was applied along the magnetic hard axis of the epitaxial Fe3Si, the angular dependence of resistivity showed an unusual zigzag behavior. However, by altering the current direction from the magnetic hard axis to the magnetic easy axis, the resistivity demonstrated a cos2(θM) behavior of the conventional anisotropic magneto-resistance effect. In addition, the anisotropic property of Fe3Si film was conducted using the Magneto-Optical Kerr Effect measurement to determine an anisotropic constant K1 and an uni-axial anisotropy Ku. The ratio of K1/ Ku was used to account for the anisotropic magnetoresistance.
In addition to the study of magnetic anisotropy, the spin injection using Fe3Si as the spin current source was investigated. Spin pumping, which generates pure spin currents by transferring the spin angular momentum of the magnetization precession to the conduction electrons, was investigated in the ferromagnetic epitaxial Fe3Si films and polycrystalline Py films covered with normal metal (Pt, Au) overlayers, respectively. With the microwave applied from a cavity and under an in-plane magnetic field, an electric voltage due to inverse spin-Hall effect (ISHE) is detected under the ferromagnetic resonance condition. The spin Hall angles of Pt and Au as deduced from the present Py and Fe3Si data are in agreement with the published values.
We also performed spin pumping experiment in Fe3Si/GaAs heterostructures. By tailoring the thickness and doping (n, p) level of the conducting GaAs buffer layer, thermal heating common of ferromagnetic metal/semiconductor heterostructure was eliminated effectively. A large ISHE voltage up to 49.2 μV was observed for Fe3Si/p-GaAs. Smaller ISHE voltage by a factor of ~0.4 was obtained for Fe3Si/n-GaAs, as scaled with its resistivity. By taking the maximum spin diffusion length estimated for n-GaAs and p-GaAs, the minimum value of spin Hall angle was estimated to be 1.910-4 and 2.810-5, respectively.

Reference
1. I. Zutic, J. Fabian, and S. Das Sarma, Rev Mod Phys 76, 323 (2004).
2. S. A. Wolf, D. D. Awschalom, R. A. Buhrman, J. M. Daughton, S. von Molnar, M. L. Roukes, A. Y. Chtchelkanova, and D. M. Treger, Science 294, 1488 (2001).
3. D. D. Awschalom and M. E. Flatte, Nat Phys 3, 153 (2007).
4. S. Datta and B. Das, Appl. Phys. Lett. 56, 665 (1990).
5. Y. K. Kato, R. C. Myers, A. C. Gossard, and D. D. Awschalom, Science 306, 1910 (2004).
6. A. Hoffmann, Phys. Status Solidi C 4, 4236 (2007).
7. G. Schmidt, D. Ferrand, L. W. Molenkamp, A. T. Filip, and B. J. van Wees, Phys. Rev. B 62, R4790 (2000).
8. H. J. Zhu, M. Ramsteiner, H. Kostial, M. Wassermeier, H. P. Schonherr, and K. H. Ploog, Phys. Rev. Lett. 87, 016601 (2001).
9. E. I. Rashba, Phys. Rev. B 62, R16267 (2000).
10. A. Fert and H. Jaffres, Phys. Rev. B 64, 184420 (2001).
11. X. Jiang, R. Wang, R. M. Shelby, R. M. Macfarlane, S. R. Bank, J. S. Harris, and S. S. P. Parkin, Phys. Rev. Lett. 94, 056601 (2005).
12. B. T. Jonker, G. Kioseoglou, A. T. Hanbicki, C. H. Li, and P. E. Thompson, Nat Phys 3, 542 (2007).
13. N. Tombros, C. Jozsa, M. Popinciuc, H. T. Jonkman, and B. J. van Wees, Nature 448, 571 (2007).
14. M. Tran, H. Jaffres, C. Deranlot, J. M. George, A. Fert, A. Miard, and A. Lemaitre, Phys. Rev. Lett. 102, 036601 (2009).
15. T. Uemura, T. Akiho, M. Harada, K. Matsuda, and M. Yamamoto, Appl. Phys. Lett. 99, 082108 (2011).
16. Y. Ando, K. Kasahara, K. Yamane, Y. Baba, Y. Maeda, Y. Hoshi, K. Sawano, M. Miyao, and K. Hamaya, Appl. Phys. Lett. 99, 012113 (2011).
17. S. P. Dash, S. Sharma, R. S. Patel, M. P. de Jong, and R. Jansen, Nature 462, 491 (2009).
18. X. H. Lou, C. Adelmann, S. A. Crooker, E. S. Garlid, J. Zhang, K. S. M. Reddy, S. D. Flexner, C. J. Palmstrom, and P. A. Crowell, Nat. Phys. 3, 197 (2007).
19. Y. Ando, K. Kasahara, K. Yamane, K. Hamaya, K. Sawano, T. Kimura, and M. Miyao, Appl. Phys. Express 3, 093001 (2010).
20. Y. Ando, K. Hamaya, K. Kasahara, Y. Kishi, K. Ueda, K. Sawano, T. Sadoh, and M. Miyao, Appl. Phys. Lett. 94, 182105 (2009).
21. J. M. Kikkawa and D. D. Awschalom, Phys. Rev. Lett. 80, 4313 (1998).
22. A. Brataas, Y. Tserkovnyak, G. E. W. Bauer, and B. I. Halperin, Phys. Rev. B 66, 060404(R) (2002).
23. Y. Tserkovnyak, A. Brataas, and G. E. W. Bauer, Phys. Rev. Lett. 88, 117601 (2002).
24. Y. Tserkovnyak, A. Brataas, and G. E. W. Bauer, Phys. Rev. B 66, 224403 (2002).
25. E. Saitoh, M. Ueda, H. Miyajima, and G. Tatara, Appl. Phys. Lett. 88, 182509 (2006).
26. H. Nakayama, K. Ando, K. Harii, T. Yoshino, R. Takahashi, Y. Kajiwara, K. Uchida, Y. Fujikawa, and E. Saitoh, Phys. Rev. B 85, 144408 (2012).
27. K. Ando, S. Takahashi, J. Ieda, H. Kurebayashi, T. Trypiniotis, C. H. Barnes, S. Maekawa, and E. Saitoh, Nat. Mater. 10, 655 (2011).
28. K. Ando, S. Takahashi, J. Ieda, Y. Kajiwara, H. Nakayama, T. Yoshino, K. Harii, Y. Fujikawa, M. Matsuo, S. Maekawa, and E. Saitoh, J. Appl. Phys. 109, 103913 (2011).
29. K. Ando and E. Saitoh, Nat. Commun. 3, 629 (2012).
30. H. Y. Inoue, K. Harii, K. Ando, K. Sasage, and E. Saitoh, J. Appl. Phys. 102, 083915 (2007).
31. O. Mosendz, J. E. Pearson, F. Y. Fradin, G. E. Bauer, S. D. Bader, and A. Hoffmann, Phys. Rev. Lett. 104, 046601 (2010).
32. O. Mosendz, V. Vlaminck, J. E. Pearson, F. Y. Fradin, G. E. W. Bauer, S. D. Bader, and A. Hoffmann, Phys. Rev. B 82, 214403 (2010).
33. O. Mosendz, J. E. Pearson, F. Y. Fradin, S. D. Bader, and A. Hoffmann, Appl. Phys. Lett. 96, 022502 (2010).
34. Z. Feng, J. Hu, L. Sun, B. You, D. Wu, J. Du, W. Zhang, A. Hu, Y. Yang, D. M. Tang, B. S. Zhang, and H. F. Ding, Phys. Rev. B 85, 214423 (2012).
35. H. Y. Hung, G. Y. Luo, Y. C. Chiu, P. Chang, W. C. Lee, J. G. Lin, S. F. Lee, M. Hong, and J. Kwo, J. Appl. Phys. 113, 17C507 (2013).
36. A. Azevedo, L. H. Vilela-Leao, R. L. Rodriguez-Suarez, A. F. L. Santos, and S. M. Rezende, Phys. Rev. B 83, 144402 (2011).
37. K. Kasahara, Y. Baba, K. Yamane, Y. Ando, S. Yamada, Y. Hoshi, K. Sawano, M. Miyao, and K. Hamaya, J. Appl. Phys. 111, 07C503 (2012).
38. M. Koike, E. Shikoh, Y. Ando, T. Shinjo, S. Yamada, K. Hamaya, and M. Shiraishi, Appl. Phys. Express 6, 023001 (2013).
39. J. C. Rojas-Sanchez, M. Cubukcu, A. Jain, C. Vergnaud, C. Portemont, C. Ducruet, A. Barski, A. Marty, L. Vila, J. P. Attane, E. Augendre, G. Desfonds, S. Gambarelli, H. Jaffres, J. M. George, and M. Jamet, Phys. Rev. B 88, 064403 (2013).
40. E. Shikoh, K. Ando, K. Kubo, E. Saitoh, T. Shinjo, and M. Shiraishi, Phys. Rev. Lett. 110, 127201 (2013).
41. Y. Ando, K. Ichiba, S. Yamada, E. Shikoh, T. Shinjo, K. Hamaya, and M. Shiraishi, Phys. Rev. B 88, 140406 (2013).
42. M. Hong, H. S. Chen, J. Kwo, A. R. Kortan, J. P. Mannaerts, B. E. Weir, and L. C. Feldman, J. Cryst. Growth 111, 984 (1991).
43. S. H. Liou, S. S. Malhotra, J. X. Shen, M. Hong, J. Kwo, H. S. Chen, and J. P. Mannaerts, J. Appl. Phys. 73, 6766 (1993).
44. Y. L. Hsu, Y. J. Lee, Y. H. Chang, M. L. Huang, Y. N. Chiu, C. C. Ho, P. Chang, C. H. Hsu, M. Hong, and J. Kwo, J. Cryst. Growth 301, 588 (2007).
45. J. Herfort, H. P. Schonherr, and K. H. Ploog, Appl. Phys. Lett. 83, 3912 (2003).
46. J. Herfort, H. P. Schonherr, K. J. Friedland, and K. H. Ploog, J Vac Sci Technol B 22, 2073 (2004).
47. M. Bowen, K. J. Friedland, J. Herfort, H. P. Schonherr, and K. H. Ploog, Phys. Rev. B 71, 172401 (2005).
48. H. Vinzelberg, J. Schumann, D. Elefant, E. Arushanov, and O. G. Schmidt, J. Appl. Phys. 104, 093707 (2008).
49. A. Ionescu, C. A. F. Vaz, T. Trypiniotis, uuml, C. M. rtler, Garc, iacute, H. a-Miquel, J. A. C. Bland, M. E. Vickers, R. M. Dalgliesh, S. Langridge, Y. Bugoslavsky, Y. Miyoshi, L. F. Cohen, and K. R. A. Ziebeck, Phys. Rev. B 71, 094401 (2005).
50. Robert C O'handley, Modern magnetic materials: principles and applications, Wiley Interscience, New York, 1999, p.579.
51. Y. C. Liu, P. Chang, S. Y. Huang, L. J. Chang, W. C. Lin, S. F. Lee, M. Hong, and J. Kwo, J. Appl. Phys. 109, 07D508 (2011).
52. M. Goto and T. Kamimori, J Phys Soc Jpn 52, 3710 (1983).
53. K. Lenz, E. Kosubek, K. Baberschke, H. Wende, J. Herfort, H. P. Schonherr, and K. H. Ploog, Phys. Rev. B 72, 144411 (2005).
54. J. Herfort, H. P. Schonherr, and B. Jenichen, J. Appl. Phys. 103, 07B506 (2008).
55. M. Brockmann, M. Zolfl, S. Miethaner, and G. Bayreuther, J Magn Magn Mater 198-99, 384 (1999).
56. C. Daboo, R. J. Hicken, D. E. P. Eley, M. Gester, S. J. Gray, A. J. R. Ives, and J. A. C. Bland, J. Appl. Phys. 75, 5586 (1994).
57. O. Mosendz, G. Woltersdorf, B. Kardasz, B. Heinrich, and C. H. Back, Phys. Rev. B 79, 224412 (2009).
58. R. I. Dzhioev, K. V. Kavokin, V. L. Korenev, M. V. Lazarev, B. Y. Meltser, M. N. Stepanova, B. P. Zakharchenya, D. Gammon, and D. S. Katzer, Phys. Rev. B 66, 245204 (2002).
59. A. Tsukahara, Y. Ando, Y. Kitamura, H. Emoto, E. Shikoh, M. P. Delmo, T. Shinjo, and M. Shiraishi, Phys. Rev. B 89, 235317 (2014).