自旋電子學為目前電子元件材料的熱門領域，稀磁半導體是在半導體中摻雜過渡金屬，不會影響半導體本身的電子特性，反而會使材料同時具有鐵磁性。很多研究提出稀磁半導體的磁性來源與其電子結構及材料的奈米效應有相關關係，因此我們利用軟X光吸收光譜探討稀磁性半導體材料-二氧化鈰摻雜鈷或銅奈米粒子的電子結構與其奈米效應，控制前驅物達到調整摻雜物的種類及濃度。

軟X光吸收光譜為研究二氧化鈰摻雜鈷有效的工具，分別可以提供我們鈷的L-edge、氧的K-edge以及鈰的M-edge吸收現象。從鈷的L-edge，可以發現Co2+以高自旋態存在。當摻雜濃度增加，會加強2p核電洞和3d電子的庫倫交互作用及交換交互作用。氧的K-edge，可以發現當粒子趨近奈米尺度時，氧的2p電子較為反局域性(delocalized)，與鈰的混成效應較強。鈰的M-edge，則得知CeO2奈米粒子為Ce3+和Ce4+共存，當粒子縮小奈米尺度時，Ce3+的強度將會增加。當摻雜的濃度增加時，會使得Ce3+強度被壓抑。

Dilute magnetic semiconductors (DMS) are materials in which a semiconductor is doped with a small amount of transition-metal atoms to induce magnetic properties necessary for spintronics and no deteriorate the optical and electronic properties. Recent research works indicate that the magnetic properties concerned with the electronic structure and the nanoscale effect are interesting and important. We used soft X-ray absorption to probe the electronic structure and the nanoscale effect of material-CeO2(Co).

Soft X-ray absorption (XAS) is a powerful tool for studying DMS. In this thesis, we studied XAS of CeO2(Co) with the X-ray energy tuned about Co L-edge,O K-edge, and Ce M-edge. The Co2+ ions doped in CeO2 exhibit a high spin state. Our XAS results indicate that the Coulomb interaction of Co core holes and electrons increases with the increase of concentration of Co. The hybridization between Ce and O will be enhanced as the particle size is in the nano scale regime. We also found that the Ce3+ and Ce4+ coexist in CeO2(Co) and the formation of Ce3+ is suppressed by increase of Co concentration.

[1.1] J. K. Furdyna, J. Appl. Phys. 64, R29 (1988).
[1.2] R. Fiederling, M. Keim, G. Reuscher, W. Ossau, G. Schmidt, A. Waag & L. W. Molenkamp, Nature, 402, 790 (1999).
[1.3] Y. Ohno, D. K. Young, B. Beschoten, F. Matsukura, H. Ohno & D. D. Awschalom, Nature, 402 ,790 (1999).
[1.4] H. OHNO, D. CHIBA, F. MATSUKURA, T. OMIYA, E. ABE, T. DIETL, Y. OHNO, K. OHTANI, Nature, 408,944 (2000).
[1.5] Y. D. Park, A. T. Hanbicki, S. C. Erwin, C. S. Hellberg, J. M. Sullivan, J. E. Mattson, T. F. Ambrose, A. Wilson, G. Spanos and B. T. Jonker, Science, 295, 651 (2002).
[1.6] H. Boukari, P. Kossacki, M. Bertolini, D. Ferrand, J. Cibert, S. Tatarenko, A. Wasiela, J. A. Gaj, and T. Dietl, Phys. Rev. Lett. 88, 207204 (2002).
[1.7] T. Dietl, H. Ohno, F. Matsukura, J. Cibert, D. Ferrand, Science, 287,1019 (2000).
[1.8] T. Dietl, H. Ohno and F. Matsukura, Phys. Rev. B, 63, 195205 (2001).
[1.9] S. A. Wolf, D. D. Awschalom, R. A. Buhrman, J. M. Daughton, S. von Molnár, M. L. Roukes, A. Y. Chtchelkanova and D. M. Treger, Science, 292,854 (2001).
[1.10] M. A. Garcia, J. M. Merino, E. Fernández Pinel, A. Quesada, J. de la Venta, M. L. Ruíz González, G. R. Castro, P. Crespo, J. Llopis, J. M. González-Calbet, and A. Hernando, Nano Lett., 2007, 7, pp 1489–1494.
[1.11] Lydia M. Johnson, Aaron Thurber, Joshua Anghel, Maryam Sabetian, Mark H. Engelhard, Dmitri A. Tenne, Charles B. Hanna, and Alex Punnoose, Phys. Rev. B, 82, 054419 (2010).
[1.12] R. K. Singhal, P. Kumari, A. Samariya, Sudhish Kumar, S. C. Sharma, Y. T. Xing, and Elisa B. Saitovitch, J. Appl. Phys. 109, 063907 (2011).
[1.13] Y. Yamamoto, T. Miura, M. Suzuki, N. Kawamura, H. Miyagawa, T. Nakamura, K. Kobayashi, T. Teranishi1, and H. Hori, Phys. Rev. Lett., 93, 116801 (2004).
[1.14] F. S. Galasso, [Structure and Properties of Inorganic Solids.], Pergamon, Oxford (1970).
[1.15] S. Tsunekawa, T. Fukuda, and A. Kasuya, J. Appl. Phys., 87, 1318 (2000).
[1.16] Gschneidner K A Jr, Rare Earth Alloys (1961).
[1.17] Lawrence J. M., Riseborough P. S. and Parks R. D., Rep. Prog. Phys. ,44, 1, (1981).
[1.18] Wuilloud E., Delley B., Schneider W.-D. and Baer Y., Phys. Rev. Lett., 53, 202 (1984).
[1.19] Johansson B., Phil. Mag., 30, 469 (1974).
[1.20] Krill G., Kappler J. P., Meyer A., Abadli L. and Ravet M. F., J . Phys. Met. Phys., 11, 1713 (1981).
[1.21] Fujimori A., Phys. Rev. B, 28, 2281 (1983).
[1.22] Bianconi A., Campagna M., Stizza S., and Davoli I.,Phys. Rev. B, 24, 6139 (1981).
[1.23] Frank de Groot, Akio Kotani, [Core Level Spectroscopy Of Solids.], Taylor & Francis Group (2008).
[1.24] J. D. Jackson, Classical Electrodynamics, Wilwy (1999).
[1.25] W. B. Wu, 錳與鈷氧化物之軌域極化與電子關聯, National Chiao Tung University, 2006.
[1.26] P. Hohenberg and W. Kohn, Physical Review, 136, B864 (1964).
[1.27] W. Kohn and L. J. Sham, Physical Review, 140, A1133 (1965).
[1.28] Stephen Blundell, Magnetism in Condensed Matter, OXFORD (2001).
[1.29] Sugano, Tanabe, & Kaimura, Multiplets of transition-metal ion in crystal (2010).

[2.1] 吳泰伯, 許樹恩, X光繞射原理與材料結構分析, 中國材料學會。
[2.2] http://www.srrc.gov.tw/chinese/img/about/c-lightsource-4-l.jpg
[2.3] E.-E. Koch, editor, Hanbook on synchrotron radiation, Vol 1a, chapter 2, North-Holland (1983).
[2.4] G. V. Marr, editor, Hanbook on synchrotron radiation, Vol 2, chapter 1, North-Holland (1987).
[2.5] http://www.srrc.gov.tw/chinese/img/about/c-lightsource-10.jpg
[2.6] C. T. Chen and F. Sette, Rev. Sci. Instrum. 60. 1616 (1989).
[2.7] C. T. Chen, Nucl. Instrum. Meth. A 256, 595 (1987).
[2.8] http://140.110.203.42/manage/fck_fileimage/file/bldoc/11ADRASGM.htm
[2.9] http://140.110.203.42/manage/fck_fileimage/file/bldoc/05BEPUSGM.htm

[3.1] Y. F. Shiu, “PrePARATION AND Characterization of Cobalt Doped Cerium Oxide Magnetic Nanoparticle”, NTHU (2011).
[3.2] R. J. Green, G. S. Chang, X. Y. Zhang, A. Dinia, E. Z. Kurmaev, and A. Moewes, PHYSICAL REVIEW B 83, 115207 (2011).
[3.3] F. M. F. de Groot, M. Abbate, J. van Elp, G. A. Sawatzky, Y. J. Ma, C. T. Chen and F. Sette, J. Phys.: Condens. Matter 5 2277 (1993).
[3.4] van Elp J., Weland J. L., Eskes H., Kuiper P., Sawatzky G. A., de Groot F. M. F. and Turner T. S., Phys. Rev. B, 44,6090 (1991).
[3.5] Okada K. and Kotani A., Plys. Soc Japan, 58, 3591 (1992).
[3.6] G. S. Chang, E. Z. Kurmaev, D. W. Boukhvalov, L. D. Finkelstein, S. Colis, T. M. Pedersen, A. Moewes, and A. Dinia, Phys. Rev. B 75, 195215 (2007).
[3.7] Xue-Chao Liu, Er-Wei Shi, Zhi-Zhan Chen, Tao Zhang, Yong Zhang, Bo-Yuan Chen, Wei Huang, Xi Liu, Li-Xin Song, Ke-Jin Zhou, and Ming-Qi Cui, Appl. Phys. Lett. 92, 042502 (2008).
[3.8] B. Vodungbo, F. Vidal, Y. Zheng, M. Marangolo, D. Demaille, V. H. Etgens, J. Varalda, A. J. A. de Oliveira, F. Maccherozzi and G. Panaccione, J. Phys.: Condens. Matter 20 125222 (2008).
[3.9] J.-Y. Kim, J.-H. Park, B.-G. Park, H.-J. Noh, S.-J. Oh, J. S. Yang, D.-H. Kim, S. D. Bu, T.-W. Noh, H.-J. Lin, Phys. Rev. Lett. 90, 017401 (2003).
[3.10] A. Di Trolio, R. Larciprete, S. Turchini, and N. Zema ,Appl. Phys. Lett. 97, 052505 (2010).

[3.11] J. W. Chiou, H. M. Tsai, C. W. Pao, K. P. Krishna Kumar, S. C. Ray, F. Z. Chien, and W. F. Pong, APPLIED PHYSICS LETTERS, 89, 043121,(2006).
[3.12] Z. Y. Wu, F. Jollet, S. Gota, N. Thromat, M. Gautier-Soyer and T. Petit, J. Phys.: Condens. Matter 11 7185 (1999).
[3.13] A. Bouaine, R. J. Green, S. Colis, P. Bazylewski, G. S. Chang, A. Moewes, E. Z. Kurmaev, and A. Dinia, J. Phys. Chem. C, 115 (5), pp 1556–1560 (2011).
[3.14] L. A. J. Garvie, P. R. Buseck, Journal of Physics and Chemistry of Solids 60 (1999).
[3.15] Z. Y. Wu, F. Jollet, S. Gota, N. Thromat, M. Gautier-Soyer and T. Petit, J. Phys.: Condens. Matter 11 7185 (1999).
[3.16] Journal of Physics and Chemistry of Solids, 22, 788 (2010).
[3.17] S. M. Butorin, D. C. Mancini, J.-H. Guo, N. Wassdahl, J. Nordgren, M. Nakazawa, S. Tanaka, T. Uozumi, A. Kotani, Y. Ma,, K. E. Myano, B. A. Karlin, and D. K. Shuh, Phys. Rev. Lett. 77, 574–577 (1996).
[3.18] B. T. Thole, G. van der Laan, and J. C. Fuggle, G. A. Sawatzky, R. C. Karnatak and J.-M. Esteva, Phys. Rev. B 32, 5107–5118 (1985).
[3.19] G. Kaindl, Z. Hu, and B. G. Muller, J. Alloys Compd. 246, 177 (1997).
[3.20] S. W. Huang, “Multiferroic Transitions and Low-Energy Excitation of Quantum Spin Systems”, NCTU, 2010.
[3.21] J. Ghijsen, L. H. Tjeng, J. van Ele, H. Eskes, J. Westerink, G. A. Sawatzky, and M. T. Czyzyk, Phys. Rev. B. 38, 11322 (1988).
[3.22] J. Ghijsen, L. H. Tjeng, H. Eskes, G. A. Sawatzky, and R. L. Johnson,Phys. Rev. B. 42, 2268 (1990).
[3.23] L. H. Tjeng, C. T. Chen, and S.-W. Cheong, Phys. Rev. B 45, 8205 (1992).
[3.24] L. H. Tjeng, C. T. Chen, and S.-W. Cheong, Phys. Rev. B 45, 8205 (1992).
[3.25] M. Grioni, J. F. van Acker, M. T. Czyˇzyk, and J. C. Fuggle, Phys. Rev.B 45, 3309 (1992).
[3.26] M. Finazzi, G. Ghiringhelli, O. Tjernberg, Ph. Ohresser, and N. B.Brookes, Phys. Rev. B 61, 4629 (2000).
[3.27] H. Eskes, L. H. Tjeng, and G. A. Sawatzky, Phys. Rev. B. 41 288 (1990).
[3.28] M. A. van Veememdaal and G. A. Sawatzky, Phys. Rev. B 49, 3473 (1994).