Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/10303
標題: 鎳鈷/鎳鈷氧化物雙層膜之結構與磁性質研究
The structures and magnetic properties of NiCo/(Ni,Co)O bilayers
作者: 劉宣吟
Liu, Hsuan-Yin
關鍵字: sputter;濺鍍;thin film;薄膜
出版社: 材料科學與工程學系所
引用: [1] W. P. Meiklejohn, C. P. Bean, Phys. Rev., 102, 1413 (1956). [2] W. P. Meiklejohn, J. Appl. Phys., 33, 1328 (1962). [3] D. Mauri, H. C. Siegmann, J. Appl. Phys., 82, 3047 (1987). [4] A. P. Malozemoff, Phys. Rev. B., 35, 3679 (1987). [5] N. C. Koon, Phys. Rev. Lett., 78, 4865 (1997). [6] T. C. Schulthess and W. H. Butler, Phys. Rev. Lett., 81, 4516 (1998). [7] A. E. Berkowitz, Kentaro Takano, J. Magn. Magn. Mater., 200, 552 (1999). [8] J. Nogues, Ivan K. Schuller, J. Magn. Magn. Mater., 192, 203 (1999). [9] J. Nogues, D. Lederman, T. J. Moran, and I. K. Schuller, Phys. Rev. Lett.,76,4624 (1996). [10] Y. Henry, S.Mangin, T. Hauet, and F. Montaigne, Phys. Rev. B, 73, 134420 (2006). [11] F. Canet, C. Bellouard, S. Mangin, C. Chatelain, C. Senet, R. Siebrecht, V. Leiner, and M. Piecuch, Eur. Phys. J. B, 34, 381 (2003). [12] J. Nogues, I.K. Schuller, unpublished (1997). [13] K.-W. Lin, Y.-M. Tzeng, Z.-Y. Guo, C.-Y. Liu, and J. van Lierop, J. Magn. Magn. Mater. 304, e124 (2006). [14] H. Ouyang, K.-W. Lin, C.-C. Liu, S.-C. Lo, Y.-M. Tzeng, Z.-Y. Guo, and J. van Lierop, Phys. Rev. Lett. 98, 097204 (2007). [15] D. Z. Yang, J. Du, L. Sun, X. S. Wu, X. X. Zhang, and S. M. Zhou, Phys. Rev. B 71, 144417 (2005) [16] Nicola A. Spaldin,”Magnetic materials”. [17] 金重勳主編,”磁性技術手冊”,中華民國磁性技術協會。 [18] David Jiles,”Interoduction to magnetism and magnetic materials”,Chapman & Hall. [19] J. Noguesa, J. Sort, V. Langlais, V. Skumryev, S. Surinach, J.S. Munoz, M.D. Baro, Physics Reports, 422, 65 (2005). [20] A.E. Berkowitz, Kentaro Takano, J. Magn. Magn. Mater. 200, 552 (1999). [21] L. Neel, Ann Phys., 2, 61 (1967). [22] A.P. Malozemoff, Phys. Rev. B, 35, 3679 (1987). [23] D. Mauri, H.C. Seigmann et al., J. Appl. Phys. 62, 3047 (1987). [24] N. Koon, Phys. Rev. Lett. 78, 4865 (1997). [25] T.Ambrose, R.L. Sommer, C.L. Chien, J. Magn. Magn. Mater. 177-181, 1235 (1998). [26] A.Baruth, D. J. Keavney, J. D. Burton, K. Janicka, E. Y. Tsymbal, L. Yuan, S. H. Liou, and S. Adenwalla1, Phys. Rev. B 74, 054419 (2006). [27] 魏德新、許瑤真,”影像式光電子顯微術於磁性薄膜及微結構研究的介紹”,物理雙月刊廿六卷四期。 [28] D. Thompson et. al., IEEE Trans.MAG-11, 1036 (1975). [29] Modern Magnetic Materials, R. C. O.’Handley, John Wiley and Sons, Inc. New York (2000). [30] B. Dieny, V. S. Speriosu, S. S. P. Parkin, B. A. Gurney, D.R. Wilhoit, and D.Mauri, Phys. Rev. 43,1297 (1991). [31] P. P. Freitas, J. L. Leal, T. S. Plaskett, L. V. Melo, and J. C. Soares, J. Appl. Phys. 75, 6480 (1994). [32] T. C. Anthony, J. Brug, and S. Zhang, IEEE Trans. Magn. 30, 3819 (1994). [33] C.-L. Lin, J. M. Sivertsen, and J. H. Judy, IEEE Trans. Magn. 30, 3834 (1994). [34] J. Fujikata, K. Isihara, K. Hayashi, H. Yamamoto, and K. Yamada, IEEE Trans.Magn. 31, 3936 (1995). [35] B. Dieny, V. S. Speriosu, S. S. P. Parkung, B.A. Gurney, D. R. Wilhoit, and D. Mauri, Phys. Rev., 43, 1297 (1991). [36] J. Nogues, J. Sort, V. Langlais, V. Skumryev, S. Surinach, J.S. Munoz, M.D. Baro, Physics Reports 422, 65 (2005). [37] P. Kappenberger, S. Martin, Y. Pellmont, H. J. Hug, J. B. Kortright, O. Hellwig, and E. E. Fullerton, Phys. Rev. Lett., 91, 267202 (2003). [38] M. N. Baibich, J. M. Broto, A. Fert, F. Nguyen Van Dau and F. Pctroff, Phys. Rev. Lett., 61, 2472 (1998). [39] Magnetism, eds. E. du Tremolet de Lacheisserie, Damien Gignoux, and Michel Schlenker, Kluwer Academic Publishers (2002). [40] R. R. Katti, proceedings of the IEEE, 91, 687 (2003). [41] J.S. Moodera et. al.,Phys. Rev. Lett. 74,3273 (1995). [42] G. A. Prinz, Science 282, 1660 (1998). [43] L. Geppert, IEEE Spectrum, 49, March (2003). [44] Minshen Tan, Hua-Ching Tong, Swie-In Tan, and Robert Rottmayer, J. Appl. Phys. 79, 5012 (1996). [45] T. B. Massalski et al., “Binary Alloy Phase Diagrams“, ASM International(1990). [46] Adrian J. Devasahayam and Mark H Kryder, IEEE Trans. Magn. 31, 6 (1995). [47] J. J.Cuomo and S. M. Rossnagel, H. R. Kaufman, “Handbook of ion beam processing technology:principles, deposition, film modification , and synthesis”, Noyes Publication, (1989). [48] C.H.Lai, P.H.Huang, J.Appl. Phys.,95,7222 (2004). [49] 林麗娟,”X光繞射原理及其應用”,工業材料86期。 [50] Bruce M. Moskoeitz, Hitchhhiker’s Guide to magnetism. [51] 汪建民主編,”材料分析”,中國材料科學學會。 [52] David B. Williams and C. Barry Carter, “Transmission Electron Microscopy”, Plenum Press (1996). [53] 龔志榮,駱榮富,”電子顯微鏡教材大綱”。 [54] David Jiles,”Magnetism and Magnetic Materials”, Chapman & Hall,(1991). [55] J. Claudon, F. Balestro, F.W.J. Hekking, and O.Buisson, Phys. Rev. Lett. 93, 187003 (2004). [56] 楊鴻昌,”最敏感的感測元件SQUID及其前瞻性應用”,物理雙月刊廿四卷五期。 [57] L. H. Lewis, K. M. Bussmann, Rev. Sci. Instrum. 67, 3537 (1996). [58] Buschow, K. H. J., Boer, F. R. de, “Physics of magnetism and magnetic materials”. [59] 汪島軍、馬仁宏、陳亙佑、蔡斯凱、林建智,”原子力顯微鏡專利地圖及分析”。 [60] PEEM操作手冊。 [61] K. W. Lin, PhD. Thesis, State University of New York at Stony Brook,(2002). [62] K.-W. Lin, J.-Y. Guo, H.-Y. Liu, H. Ouyang, Y.-L. Chan, D.-H. Wei, and J. van Lierop, J. Appl. Phys., 103, 1 (2008). [63] J.B. Yi, J. Ding, B.H. Liu, Z.L. Dong, T. Whiteb, Y. Liu, J. Magn. Magn. Mater., 285, 224 (2005). [64] E. Girgis, R.D. Portugal, H. Loosvelt, M.J. Van Bael, I. Gordon, M. Malfait, K. Temst, C. Van Haesendonck, L.H.A. Leunissen, R. Jonckheere, Phys. Rev. Lett. 91,187202 (2003). [65] D.V. Dimitrov, S.F. Zhang, J.Q. Xiao, G.C. Hadijipanayis, C. Prados, Phys. Rev. B 58, 12090 (1998). [66] H. Ouyang, K.-W. Lin, C.-C. Liu, S.-C. Lo, Y.-M. Tzeng, Z.-Y. Guo, and J. van Lierop, Phys. Rev. Lett. 98, 097204 (2007). [67] J. Nogues, J. Sort, V. Langlais, V. Skumryev, S. Surinach, J. S. Munoz, and M. D. Baro, Phys. Rep., 422, 65 (2005). [68] T. Furubayashi and H. Mamiya, Phys. Status Solidi C, 1, 3432 (2004). [69] J. Y. Yi, G. A. Hirata, and M. L. Rudee, MRS Symposia Proceedings No. 674, (Materials Research Society, Pittsburgh, 2001), T3.4.1. [70] S. Sahoo, C. Binek, and W. Kleemann, Phys. Rev. B, 68, 174431 (2003). [71] J. Nogues, T. J. Moran, D. Lederman, I. K. Schuller, and K. V. Rao, Phys.Rev. B, 59, 6984 (1999). [72] M. R. Fitzsimmons, C. Leighton, J. Nogues, A. Hoffmann, K. Liu, C. F.Majkrzak, J. A. Dura, J. R. Groves, R. W. Springer, P. N. Arendt, V. Leiner, H. Lauter, and I. K. Schuller, Phys. Rev. B., 65, 134436 (2002). [73] J. Fassbender and J. McCord, J. Magn. Magn. Mater. (in press). [74] J. Fassbender, D. Ravelosona, and Y. Samson, J. Phys. D, 37, R179 (2004).
摘要: 
本研究利用雙離子束濺鍍系統製備鎳鈷/鎳鐵氧化物[NiCo/NiCoO]之雙層薄膜,藉由通入氧氣、氬氣混合氣體之輔助離子束,分別製備氧含量8%~41%之氧化鎳鈷薄膜,並探討其結構及磁性質。接著再以輔助離子源(End-Hall)以0~150V不同能量轟擊氧含量為26%的氧化鎳鈷薄膜,轟擊完再鍍上鎳鈷金屬薄膜,並探討經轟擊過後的結構及磁性質。

XRD研究結果顯示上層鎳鈷薄膜為具有面心立方結構之鎳鈷相(a=3.53 Å),下層之氧化鎳鈷薄膜為鹽岩結構之純鎳鈷氧化物(a=4.26 Å)或具有金屬鎳鈷相及鎳鈷氧化物之混合結構。穿透式電子顯微鏡分析顯示鎳鈷/鎳鐵氧化物雙層薄膜之晶粒大小為5~15 nm。

磁性分析顯示,氧含量為8%之鎳鈷/鎳鐵氧化物雙層薄膜在溫度為5K、外加場為20K Oe下,其磁滯曲線具有double-shifted的現象,且具有正的交換偏壓。鎳鈷/鎳鐵氧化物雙層薄膜26% 未轟擊前其交換偏壓~0 Oe,而以150V轟擊氧化鎳鈷薄膜則具有最大之交換偏壓~-400 Oe。此外,隨著轟擊能量的增加,矯頑磁力(Hc)的改變與交換偏壓(Hex)呈現相反的趨勢,此行為可歸因於適度的離子束轟擊使鎳鈷氧化物表面原子重新排列所造成的現象。

由影像式光電子顯微術(PEEM)研究的結果提供反鐵磁(NiCoO)及鐵磁(NiCo)交換耦合直接的證據。氧含量為8%之鎳鈷/鎳鐵氧化物雙層薄膜具有條紋狀的磁區。然而氧含量為30%之鎳鈷/鎳鐵氧化物雙層薄膜的磁區突然變小,這可能為反鐵磁層的磁矩重新排列,由平行方向改為垂直膜面而造成的現象。

磁電傳輸性質顯示:鎳鈷/鎳鐵氧化物雙層薄膜具有異相性磁電阻(anisotropic magnetoresistance)的性質。鎳鈷/鎳鐵氧化物雙層薄膜在低溫(77 K)有較高之磁阻率(2.85%),主要由於聲子散射降低所致。

The structural and magnetic properties of NiCo(18 nm)/(Ni,Co)O(45 nm) bilayers were investigated. X-ray diffractometry results have shown that the top NiCo layer consisted of a fcc NiCo phase (a= 3.53 Å). The bilayer bottom was either a pure rock-salt (Ni,Co)O (a= 4.26 ) or a composite [NiCo+(Ni,Co)O] phase, depending on the percent of O2/Ar ratio used during deposition. The grain sizes of these polycrystalline NiCo/(Ni,Co)O bilayers range from 5 nm to 15 nm, as revealed by Transmission electron microscopy (TEM).
A double-shifted hysteresis loop exhibiting components that were from positive or negative coupling was observed at 5 K under a field-cooling process (FC at 20 kOe) in the NiCo/(Ni,Co)O (8%O2/Ar) bilayers.
Further, an unusual exchange bias was found in NiCo/(Ni,Co)O bilayers that results from the surface of the (Ni,Co)O layer being bombarded with different Ar-ion energies using End-Hall deposition voltages (VEH) from 0 to 150 V. The largest exchange bias field, Hex~ -400 Oe at 5 K, was observed in NiCo/(Ni,Co)O bilayers (VEH= 150 V) whereas no significant Hex was found in unbombarded NiCo/(Ni,Co)O bilayers (VEH= 0 V). In addition, the coercivity, Hc, was found to change with VEH in an opposite fashion to Hex. The behavior of Hex and Hc with VEH is attributed to surface reorientation that is due to moderate ion-beam bombardment effects on the surface of the (Ni,Co)O layer.
Angular dependence of NiCo/(Ni,Co)O bilayers on Hc and Hex have shown that both positive and negative Hex was observed in zero-field-cooling process (ZFC). However, the typical negative Hex was found in the FC process indicating that the role of the cooling field is used to maintain a single FM domain state.
Direct evidence of exchange coupling between the AF (Ni,Co)O and the FM NiCo layer is provided by Photoemission electron microscopy (PEEM). The NiCo/(Ni,Co)O (8%O2/Ar) bilayer displays stripe domains which are characteristic of the exchange bias. However, a sudden change in PEEM images was observed in NiCo/(Ni,Co)O (30%O2/Ar) bilayers. This is likely due to the AF (Ni,Co)O spin reorientation from in-plane toward out-of-plane direction resulting from ion-beam bombardment.
The magnetotransport studies have shown that these NiCo/(Ni,Co)O bilayers exhibit the anisotropic magnetoresistance (AMR) behavior. The total MR ratio is larger at 77 K, ascribed to the reduced interfacial scattering between FM and AF layer.
URI: http://hdl.handle.net/11455/10303
其他識別: U0005-2407200615432400
Appears in Collections:材料科學與工程學系

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