臺灣博碩士論文加值系統

摘要
摘要
本論文的主題是以歐傑電子能譜術、低能量電子繞射、紫外光電子能譜術以及磁光柯爾效應來研究銀、鈷超薄膜長在鉑 (111) 表面上的成長模式、結構、合金形成和磁性。這些磁性包括居禮溫度、矯頑力、磁異向性和自旋反轉，而且這些磁性和薄膜成長條件、薄膜厚度、覆蓋層或緩衝層的加入與否、退火過程等都有很密切的關係。
鈷超薄膜長在鉑 (111) 表面是屬於 SK的成長模式。當薄膜厚度小於四層時，它的易軸方向垂直於薄膜表面；厚度越厚時易軸方向就轉成為平行於薄膜表面。一層的鈷/鉑 (111) 樣品經過710 K 的退火效應後，其垂直柯爾訊號有很明顯的增強現象。在鈷-鉑 (111) 系統中，鈷的厚度越厚時樣品的居禮溫度越高。鈷長在平坦的鉑 (111) 表面，其矯頑力隨鈷厚度的增加而減小；當鈷長在粗糙的鉑 (111) 表面時，其矯頑力卻不受鈷厚度的影響。銀鍍在薄的鈷-鉑 (111) 表面時，銀會抑制鈷的自旋反轉；當銀鍍在厚的鈷-鉑 (111) 表面時，銀會使樣品的易軸方向由平行於薄膜表面轉成為垂直於薄膜表面。這種SRT的現象，主要是由於銀覆蓋層的加入使得樣品的表面磁異向性常數增加的原因。鈷-鉑形成合金的過程中，銀一直保持在樣品的最上層。銀覆蓋層對樣品的垂直磁異向性有很重要的影響，它也會增加鈷-鉑 (111) 系統的居禮溫度。
在鈷-銀-鉑 (111) 系統中，當溫度夠高時銀會浮到樣品的最上層，而這種鈷和銀原子的交換也會影響鈷-鉑合金的形成。鈷、銀原子開始交換的溫度不受銀厚度的影響，而交換完成的溫度隨銀厚度的改變而改變。

Abstract
Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), ultraviolet photoelectron spectroscopy (UPS), and magneto-optical Kerr effect (MOKE) were used to study the growth mode, structure, alloy formation, and magnetic properties of Ag, Co ultrathin film on Pt (111) surface. The magnetic properties, such as Curie temperature (Tc), coercivity (Hc), magnetic anisotropy (MA), and spin reorientation transition (SRT) of the magnetic ultrathin films are significant influenced by the growth conditions, film thickness, addition of capping layer or buffer layer, and annealing process.
The growth of Co ultrathin film on Pt (111) is Stranski-Krastanov mode. The easy axis of magnetization is oriented perpendicular to the film plane as Co film thickness less than 4 ML, and changes into in-plane for thick film. A giant enhancement in the polar Kerr signals is observed after annealing 1 ML Co/Pt (111) at 710 K. The Curie temperature increases as Co thickness increases. The coercivity decreases as the Co coverage increases for the flat Pt (111) surface, but is independent of Co thickness for the sputtered one. The sitting of Ag atoms on the top of thin Co/Pt (111) film prevents the spin reversal of Co, and it changes the easy axis of magnetization from in-plane to out-of-plane for thick Co/Pt (111) film. The increasing of the surface anisotropy after Ag atom deposition may be the main mechanism that causes the representation of SRT. Ag atoms always stay on the topmost layer during the Co-Pt alloy formation. Ag capping layers have an important contribution in the perpendicular magnetic anisotropy (PMA). The Curie temperature increases after Ag overlayer deposition on Co/Pt (111) surface.
The exchange between Co and Ag atoms affects the formation of Co-Pt alloy. Ag atoms float to the top layers when annealing temperature is high enough. The starting exchange temperature is independent of Ag coverage, but the complete exchange temperature depends on the Ag film thickness.

Contents
Chapter 1 Introduction 1
Chapter 2 Basic Theories for Magnetic Uitrathin Films 4
2.1 Ferromagnetism 4
2.2 Magnetic Anisotropy Energy 6
2.3 Spin Reorientation Transition 10
2.4 Coercivity 11
Chapter 3 Experimental Environments 14
3.1 Experimental Apparatus 14
3.1.1 Auger Electron Spectroscopy (AES) 14
3.1.2 Low Energy Electron Diffraction (LEED) 18
3.1.3 Magneto-Optical Kerr Effect (MOKE) and
Surface Magneto-Optical Kerr Effect (SMOKE) 20
3.2 The Description of Experimental Operation 23
3.2.1 Sample Preparation 23
3.2.2 The Evaporation System 24
3.2.3 The Measurement of SMOKE 24
Chapter 4 Results and discussion 27
4.1 The Growth Mode and Magnetic Properties of Co
Ultrathin Film on Pt (111) 27
4.1.1 Structural Information 28
4.1.2 Easy Axis of Magnetization with Film Thickness 31
4.1.3 Curie Temperature and Critical Exponent 33
4.1.4 Coercivity for Co/flat Pt (111) and Co/sputered
Pt(111) 38
4.2 The Structure and Magnetic Properties of Ag/Co/Pt
(111) 43
4.2.1 The LEED Pattern and Structure 43
4.2.2 Annealing Effect on The LEED Intensity and
Structure 46
4.2.3 Strange in Hc Due to Non-magnetic Ag Overlayer 50
4.2.4 Annealing Effect on Magnetic Properties 53
4.2.5 Ag Capping Layers Induce Enhancement of Hc and
Tc 58
4.2.6 Ag Capping Layers Induce Spin Reorientation
Transition 66
4.3 Exchange Effect and Alloy Formation of Co/Ag/ Pt
(111) 79
4.3.1 Temperature Dependence of Exchange Effect and
Thickness Dependence of Alloy Formation 79
4.3.2 The Possible Magnetic Property 86
Chapter 5 Conclusions and Further Studies 88
Reference 91
Publication 102

References:
[1] F. J. A. den Broeder, W. Hoving, and P. J. H. Bloemen, J. Magn. Magn. Mater. 93, 562 (1991).
[2] G. H. O. Daalderop, P. J. Kelly, and M. F. H. Schuurmans, Phys. Rev. B 44, 12054 (1992).
[3] P. F. Carcia, J. Appl. Phys. 63, 5066 (1988).
[4] K. Nakamura, S. Tsunashima, and S. Uchiyama, IEEE Trans. Magn. Mag 25, 3758 (1989).
[5] N. W. E. McGee, M. T. Johnson, J. J. de Vries, and J. aan de Stegge, J. Appl. Phys. 73, 3418 (1993).
[6] T. C. Huang, R. Sayoy, R. F. C. Farrow, and R. F. Marks, Appl. Phys. Lett. 62, 1353 (1993).
[7] B. Ujfalussy, L. Szunyogh, P. Bruno, and P. Weinberger, Phys. Rev. Lett. 77, 1805 (1996).
[8] C. J. Lin and G. L. Gorman, Appl. Phys. Lett. 61, 1600 (1992).
[9] A. Gerber, A. Milner, I. Ya. Korenblit, M. Karpovsky, A. Gladkikh, and A. Sulpice, Phys. Rev. B 57, 13667 (1998).
[10] F. Parent, J. Tuaillon, L. B. Stern, V. Dupuis, B. Prevel, A. Perez, P. Melinon, G. Guirand, R. Morel, A. Barthelemy, and A. Fert, Phys. Rev. B 55, 3683 (1997).
[11] Y. D. Zhang, J. I. Budnick, W. A. Hines, C. L. Chien, and J. Q. Xiao, Appl. Phys. Lett. 72, 2053 (1998).
[12] S. Honda, M. Nawate, M. Tanaka, and T. Okada, J. Appl. Phys. 82, 764 (1997).
[13] Takashi Sugiyama, and Osamu Nittono, Thin Solid Films 334, 206 (1998).
[14] F. Huang, G. J. Mankey, and R. F. Willis, J. Appl. Phys. 75, 6406 (1994).
[15] J. Ferré, J. P. Jamet, J. Pommier, P. Beauvillain, C. Chappert, R. Mégy, P. Veillet, J. Magn. Magn. Mater. 174, 77 (1997).
[16] Brad N. Engel, Michael H. Wiedmann, and Charles M. Falco, J. Appl. Phys. 75, 6401 (1994).
[17] Brad N. Engel, Michael H. Wiedmann, Robert A. Van Leeuwen, and Charles M. Falco, J. Appl. Phys. 73, 6192 (1993).
[18] W. Weber, C. H. Back, A. Bischof, D. Pescia, and R. Allenspach, Nature 374, 788 (1995).
[19] Brad N. Engel, Michael H. Wiedmann, Robert A. Van Leeuwen, and Charles M. Falco, Phys. Rev. B 48, 9894 (1993).
[20] W. L. ÓBrien, T. Droubay, and B. P. Tonner, Phys. Rev. B 54, 9297 (1996).
[21] Yonko Millev and Jurgen Kirschner, Phys. Rev. B 54, 4137 (1996).
[22] P. J. Jensen and K. H. Bennemann, Phys. Rev. B 52, 16012 (1995).
[23] K. Umeda, Y. Fujiwara, T. Matsumoto, K. Nakagawa, A. Itoh, J. Magn. Magn. Mater. 156, 75 (1996).
[24] R. H. Victora, J. M. Maclaren, Phys. Rev. B 47, 11583 (1993).
[25] Y. Suzuki, H. Y. Hwang, S. W. Cheony, and R. B. Van Cover, Appl. Phys. Lett. 71, 140 (1997).
[26] C. H. Lee, R. F. C. Farrow, C. J. Lin, and E. E. Marinero, Phys. Rev. B 42, 11384 (1990).
[27] G. Y. Guo, and H. Ebert, J. Magn. Magn. Mater. 156, 173 (1996).
[28] C. Leroux, M. C. Cadeville, V. Pierron-Bohnes, G. Inden, and F. Hing, J. Phys. F: Met. Phys. 18, 2033 (1989).
[29] T. Massalski, Binary Alloy Phase Diagram (American Society for Metals, Metals Park, OH, 1990), Vol 2.
[30] G. Moraϊtis, J. C. Parlebas, and M. A. Khan, J. Phys.: Condens. Matter 8, 1151 (1996).
[31] J. Thiele, N. T. Barret, R. Belkhou, C. Guillot, and H. Koundi, J. Phys.:Condens. Matter 6, 5025 (1994).
[32] G.. Ertl, J. Kuppers, “Low Energy Electrons and Surface Chemistry “ 2nd edition (1985) pp. 2.
[33] “ Morden Magnetic Materials (Principles and Applications)” edited by Robert C. O’Handley (John Wiley & Sons, Inc. Canada, 2000) pp.20~21.
[34] “ Introduction to Magnetic Materials” edited by B. D. Cullity (Addison-Wesley,1972) pp. 128.
[35] C. M. Schneider, Phys. Rev. Lett. 64, 1059 (1990).
[36] Hyuk j. Choi, Phys. Rev. Lett. 82, 1947 (1992).
[37] Roy F. Willis, Progress in Surf. Sci. 54, 277 (1997).
[38] Z. Q. Qiu, J. Pearson, and S. D. Bader, Phys. Rev. B 49, 8797 (1994).
[39] S. T. Bramwell, and P. C. W. Holdsworth, J. Phys.: Condens. Matter 5, L53 (1993).
[40] C. Liu, and S. D. Bader, J. Appl. Phys 67, 5758 (1990).
[41] H. J. Elmers, J. Hauschild, H. Höche, and U. Gradmann, Phys. Rev. Lett. 73, 898 (1994).
[42] Z. Q. Qiu, J. Pearson, and S. D. Bader, Phys. Rev. B 49, 8659 (1992).
[43] H. J. Elmers. J. Hauschild, G. Liu, and U. Gradmann, J. Appl. Phys. 79, 4985 (1996).
[44] “ Physics of Magnetism” edited by Soshin Chikazumi ( John Wiley & Sons, Inc. New York. London, 1964) pp.147.
[45] J. H. Van Vleck, Phys. Rev. 52, 1178 (1937).
[46] W. Weber, R. Allenspach, and A. Bischof, Appl. Phys. Lett. 70, 520 (1997)
[47] F. Wilhelm, P. Poulopoulos, P. Srivastava, H. Wende, M. Farle, and K. Baberschke, Phys. Rev. B 61, 8647 (2000)
[48] Toshiki Kingetsu, Jpn. J. Appl. Phys. 13, L106 (1994).
[49] D. Weller, J. Stöhr, R. Nakajima, A. Carl, M. G. Samant, C. Chappert, R. Mégy, P. Beauvillain, P. Veillt, and G. A. Held, Phys. Rev. Lett. 75, 3752 (1995).
[50] C. A. F. Vaz, and J. A. C. Bland, Phys. Rev. B 61, 3098 (2000).
[51] B. D. Hermsmeier, R. F. C. Farrow, C. H. Lee, E. E. Marinero, J. Appl. Phys. 69, 5646 (1991).
[52] A. Dinia, N. Persat, and H. Danan, J. Appl. Phys. 84, 5668 (1998).
[53] A. N. Anisimov, W. Platow, P. Poulopoulos, W. Wisny, M. Farle, K. Baberschke, P. Isberg, B. Hjörvarsson, and R. Wäppling, J. Phys.: Condens. Matter 9, 10581 (1997).
[54] V. I. Gavrilenko, and Ruqin Wu, Phys. Rev. B 60, 9539 (1999).
[55] I. B. Chung, Y. M. Koo, and J. M. Lee, J. Appl. Phys. 87, 4205 (2000).
[56] N.- H. Cho, Kannan M. Krishnan, C. A. Lucas, and R. F. C. Farrow J. Appl. Phys. 72, 5799 (1992).
[57] Patrick Brubo, J. Appl. Phys. 64, 3153 (1988).
[58] J. M. Maclaren, J. Appl. Phys. 79, 5828 (1996).
[59] D. S. Chung, C. A. Allent, and R. C. Öhandley, Phys. Rev. B 49, 15048 (1994).
[60] A. Berger, U. Linke, and H. Oepen, Phys. Rev. Lett. 68, 839 (1992).
[61] R. K. Kawakami, E. J. Escorcia-Aparicio, and Z. Q. Qiu, Phys. Rev. Lett. 77, 2570 (1996).
[62] H. J. Choi, Z. Q. Qiu, J. Pearson, J. S. Jiangd Li, and S. D. Bader, Phys. Rev. B 57, R12713 (1998).
[63] L. Szunyogh, B. Üjfalussy, C. Blaas, U. Pustogowa, C. Sommers, P. Weinberger, Phys. Rev. B 56, 14036 (1997).
[64] J. H. Kim, and S. C. Shin, J. Appl. Phys. 80, 3121 (1996).
[65] B. N. Engel, C. D. England, R. A. Van Leeuwen, M. H. Wiedmann, and C. M. Falco, Phys. Rev. Lett. 67, 1910 (1991).
[66] H. J. G. Draaisma, W. J. M de Jonge, and F. J. A. den Broeder, J. Magn. Magn. Mater. 66, 351 (1987).
[67] J. M. Mac Laren, and R. H. Victora, Appl. Phys. Lett. 66, 3377 (1995).
[68] “ Ultrathin Magnetic Structure I ” edited by B. Heinrich, and J. A. C. Bland (Springer-Verlag, Berlin Heidrlberg, 1994) pp.66~70.
[69] V. Grolier, J. Ferré, A. Maziewski, E. Stefanowicz, and D. Renard, J. Appl. Phys. 73, 5939 (1993).
[70] “ Introduction to Magnetism and Magnetic Recording” edited by R. Lawrence Comstock ( John Wiley & Sons, Inc. 1999) pp. 169~170.
[71] U. Bovensiepen, Hyuk J. Choi, and Z. Q. Qiu, Phys. Rev. B 61, 3235 (2000).
[72] F. Huang, M. T. Kief, G. J. Mankey, and R. F. Willis, Phys. Rev. B 49, 3962 (1994).
[73] A. Berger and H. Hopster, Phys. Rev. Lett. 76, 519 (1996).
[74] M. Farle, B. Mirwald-Schulz, A. N. Anisimov, W. Platow, and K. Baberschke, Phys. Rev. B 55, 3708 (1997).
[75] B. Schulz and K. Baberschke, Phys. Rev. B 50, 13467 (1994).
[76] M. Farle, W. Platow, A. N. Anisimov, P. Poulopoulos, and K. Baberschke, Phys. Rev. B 56, 5100 (1997).
[77] G. Garreau, E. Beaurepaire, and K. Ounadjela, Phys. Rev. B 53, 1083 (1996).
[78] G. Garreau, M. Farle, E. Beaurepaire, and J. P. Kappler, J. Magn. Magn. Mater. 184, 289 (1998).
[79] S. Hope, E. Gu, B. Choi, and J. A. C. Bland , Phys. Rev. Lett. 80, 1750 (1998).
[80] Minn-Tsong Lin, W. C. Lin, C. C. Kuo, and C. L. Chiu, Phys. Rev. B 62, 14268 (2000).
[81] S. U. Jen, T. P. Chen, and B. L. Chao, Phys. Rev. B 48, 12789 (1993).
[82] “ Introduction to Magnetic Materials” edited by B. D. Cullity (Addison-Wesley,1972) pp16~20, 413~417
[83] D.Givord, P.tenaud, T.Viadieu, IEEE Trans. Magn. 24, 1921 (1988).
[84] H. S. Bergh, B. Gergen, H. Neinhaus, A. Majumdar, W. H. Weinberg, E. W. McFarland, Rev. Sci. Instrum. 70, 2087 (1999).
[85] C. Chappert, P. Beauvillain, P. Bruno, J. P. Chauyineau, M. Galtier, K. Le Dang, C. Marliére, R. Mégy, D. Renard, J. P. Renard, J. Seiden, F. Trigui, P. Veillet, J. Magn. Magn. Mater. 93, 319 (1991).
[86] Xiao Hu, Phys. Rev. B 55, 8382 (1997).
[87] E. Kolb, M. Mulloy, C. Dupas, M. Galtier, D. Renard, J. P. Renard, F. Trigui, E. Vélu, J. Magn. Magn. Mater. 148, 315 (1995).
[88] P. Bruno, G. Bayreuther, P. Beauvillain, C. Chappert, G. Lugert, D. Renard, J. P. Renard, and J. Seiden, J. Appl. Phys. 68, 5759 (1990).
[89] Y. K. Kim, and M. Oliveria, J. Appl. Phys. 74, 1233 (1993).
[90] M. A. Akhter, D. J. Mapps, Y. Q. Ma Tan, A. P. Long, and R. Doole, J. Appl. Phys. 81, 4122 (1997).
[91] S. Shiomi, T. Nakabayashi, M. Okada, T. Kobayashi, and M. Masuda, Jpn. J. Appl. Phys. 32, part I, 791 (1993).
[92] S. Shiomi, T. Nakaki Ta, R. Tanaka, T. Kabayashi, and M. Masuda, Jpn. J. Appl. Phys. 35, L213 (1996).
[93] W. Y. Lee, B-ch. Choi, Y. B. Xu, and J. A. C. Bland, Phys. Rev. B 60, 10216 (1999).
[94] A. B. Chizhik, S. L. Gnatchenko, D. N. Merenkov, L. T. Baczewski, A. Wawro, H. Szymczmczak, and H. Gamari-Seale, J. Appl. Phys. 84, 5105 (1998).
[95] D. W. Taylor, V. Villas-Boas, Q. Lu, M. F. Rossignol, F. P. Missell, D. Givord, and S. Hirosaws, J. Magn. Magn. Mater. 130, 225 (1994).
[96] Y. Ma, and S. T. Chui, J. Appl. Phys. 88, 1583 (2000).
[97] V. Karanasos, I. Panagiotopouls, D. Niarchos, H. Okumura, and G. C. Hadjipanayis, J. Appl. Phys. 88, 2740 (2000).
[98] A. Ramesh, M. R. Govindaraju, D. C. Jiles, S. B. Biner, and J. M. Roderick, J. Appl. Phys. 79, 5453 (1996).
[99] S. Shiomi, T. Nakakita, T. Kobayashi, and M. Masuda, Jpn. J. Appl. Phys. 32, part II, L1058 (1993).
[100] H. Tamane, Y. Maeno, and M. Kobayashi, Appl. Phys. Lett. 62, 1562 (1993).
[101] G. A. Berteo, and R. Sindair, Appl. Phys. Lett. 64, 3337 (1994).
[102] P. F. Carcia, S. I. Shar, and W. B. Zeper, Appl. Phys. Lett. 56, 2345 (1990).
[103] M. T. Kief, G. J. Mankey, and P. F. Willis, J. Appl. Phys. 69, 5000 (1991).
[104] M. E. Backley, F. O. Schumann, and J. A. C. Bland, Phys. Rev. B 52, 6596 (1995).
[105] “Surface Science Techniques” edited by J. M. Walls, and R. Smith ( Elsevier Science Ltd, 1994) PP. 26-27.
[106] M. P. Seah, and W. A. Dench, Surf. Int. Anal. 1, 2 (1979).
[107] “Ultrathin Magnetic Structure II” edited by B. Heinrich, and J. A. C. Bland (Springer Verlag, Berlin Heidelberg, New York, 1994) PP. 297.
[108] M. Mansuripur, J. Appl. Phys. 67, 6466 (1990).
[109] Z. Q. Qiu, J. Pearson, and S. D. Bader, Phys. Rev. B 45, 7211 (1992).
[110] L. Argile, and G. E. Rhead, Surf. Sci. Rep. 10, 277 (1989).
[111] J. S. Tsay, and C. S. Shern, Surf. Sci. 396, 313 (1998).
[112] G. R. Harp, D. Weller, T. A. Rabedeau, and R. F. C. Farrow, M. F. Toney, Phys. Rev. Lett. 71, 2493 (1993).
[113] C. S. Shern, J. S. Tsay, H. Y. Her, Y. E. Wu, and R. H. Chen, Surf. Sci. 429, L497 (1999).
[114] J. Thiele, C. Boeglin, K. Hricovini, and F. Chevrier, Phys, Rev. B 53, R11934 (1996).
[115] Z. Zhang, P. E. Wigen, and S. S. P. Parkin, J. Appl. Phys. 69, 5649 (1991).
[116] P. Beauvillain, A. Bounouh, C. Chappert, Mégy, S. Ould-Mahfoud, J. P. Renard, P. Veillet, D. Weller, and J. Corno, J. Appl. Phys. 76, 6078 (1994).
[117] W. B. Zeper, F. J. A. M. Greidanus, P. F. Carcia, and C. R. Fincher, J. Appl. Phys. 65, 4971 (1989).
[118] F. J. A. den Broeder, D. Kuiper, H. C. Donkersloot, and W. Hoving, Appl. Phys. A 49, 507 (1989).
[119] R. Allenspeach, and A. Bischof, Phys. Rev. Lett. 69, 3385 (1992).
[120] M.- T. Lin, J. Shen, W. Kuch, H. Jenniches, M. Klaua, C. M. Schneider, and J. Kirschner, Phys. Rev. B 55, 5886 (1997).
[121] W. J. Antel, Jr. M. M. Schwickert, and Tao Lin, Phys. Rev. B 60, 12933 (1999).
[122] M. C. Saint-Lager, R. Baudoing-Savois, M. De Santis, P. Dolle, and Y. Gauthier, Surf. Sci. 418, 485 (1998).
[123] A. Atrei, U. Bardi, M. Galeotti, G. Rovida, M. Torrini, and E. Zanazzi, Surf. Sci. 339, 323 (1995).
[124] C. S. Shern, J. S. Tsay, H. Y. Her, Y. E. Wu, and R. H. Chen, Surf. Sci. 429, L497 (1999).
[125] H. Brändle, D. Weller, J. C. Scott, S. S. P. Parkin, C.-J. Lin, IEEE Trans. Magn. 28, 2967 (1992).
[126] F. O. Schumann, S. Z. Wu, G. J. Mankey, and R. F. Willis Phys. Rev. B 56, 2668 (1997).
[127] C. A. Ballentine, R. L. Fink, J. Araya-Pochet, and J. L. Erskine, Phys. Rev. B 41, 2631 (1990).
[128] Hyuk J. Choi, R. K. Kawakami, Ernesto J. E. Apaeicio, and Z. Q. Qiu, Phys. Rev. Lett. 82, 1947 (1999).
[129] C.-H. Chang, and M. H. Kryder, J. Appl. Phys. 75, 6864 (1994).
[130] T. Michley, and G. Comsa, Phys. Rev. B 44, 8411 (1991).
[131] M. Choe, and M. Steinback, J. Appl. Phys. 85, 5777 (1999).
[132] D. Weller, G. R. Harp, R. F. C. Farrow, A. Cebollada, and J. Sticht, Phys. Rev. Lett. 72, 2097 (1994).
[133] R. Ferré, K. Ounadjela, J. M. Geoage, L. Piraux, and S. Dubois, Phys. Rev. B 56, 14066 (1997).
[134] B. Dacuna, J. Mira, M. C. Blanco, M. A. Lopez-Quintela, and J. Rivas, J. Magn. Magn. Mater. 203, 123 (1999).
[135] M. T. Paffett, C. T. Campbell, and T. N. Taylor, Langmuir 1, 741 (1985).
[136] M. Tikhov, and E. Bauer, Surf. Sci. 223, 73 (1990).
[137] K. F. Wojciechowski, Surf. Sci. 437, 285 (1999).
[138] S. Ferrer, J. Alvarez, E. Lundgren, X. Torrelles, P. Fajardo, F. Boscherini, Phys. Rev. B 56, 9848 (1997).
[139] D. Weller, H. Brändle, G. Gorman, C-J. Lin, H. Notarys, Appl. Phys. Lett. 61, 2726 (1992).
[140] S. Gallego, C. Ocal, M. C. Munoz, F. Soria, Phys. Rev. B 56, 12319 (1997).
[141] D. M. Schaller, D. E. Burgler, C. M. Schmidt, F. Meisinger, and H. J. Guntherodt, Phys. Rev. B , 14516 (1999).
[142] P. Krams, F. Lauks, R. L. Stamps, B. Hillebrands, and G. Güntherodt, Phys. Rev. Lett. , 3674 (1992).
[143] A. Barbier, R. Belkhou, P. Ohresser, V. Da Costa, C. Guillot, B. Carriere, and J. P. Deville, Surf. Sci. 414, 170 (1998).
[144] M. Copel, M. C. Reuter, E. Kaxiras, and R. M. Tromp, Phys. Rev. Lett. 63, 632 (1989).
[145] D. Kandel, and E. Kaxiras, Phys. Rev. Lett. 75, 2742 (1995).
[146] J. S. Tsay, and C. S. Shern, Chinese J. Phys. 34(2), 130 (1996).
[147] H. Roder, R. Schuster, H. Brune, and K. Kem, Phys. Rev. Lett. 71, 2086 (1993).
[148] I.- S. Hwang, T. C. Chang, T. T. Tsong, Phys. Rev. Lett. 80, 4229 (1998).
[149] W. F. Egelhoff, Jr. and D. A. Sterigerwald, J. Vac. Sci. Technol. A 7, 2167 (1989).
[150] M. Canepa, P. Cantini, O. Ricciardi, S. Terreni, and L. Mattern, Surf. Sci. 429, 34 (1999).
[151] P. Schieffer, M. C. Hanf, C. Krembel, and G. Gewinner, Surf. Sci. 446, 175 (2000).
[152] L. Z. Mezey, and J. Giber, Jpn. J. Appl. Phys. 21, 1569 (1982).
[153] J. S. Tsay, and C. S. Shern, J. Vac. Sci. Technol. A14, 2522 (1996).
[154] C. S. Shern, S. L. Chen, J. S. Tsay, and R. H. Chen, Phys. Rev. B 58, 7328 (1998).