Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/16991
標題: Magneto Impedance Behaviors of Pseudo spin Valve
類自旋閥的磁阻抗效應研究
作者: Hung, Ruei-Feng
洪瑞峰
關鍵字: Spin Valve
自旋閥
Impedance
磁阻抗
出版社: 物理學系所
引用: 中文參考書目 [a] 鄭振東,實用磁性材料,台北市,全華科技圖書公司。 [b] 陳錫桓,電磁學,台北市,中央圖書出版社。 英文參考文獻 [1] R. Hunt, IEEE Trans. Magn., MAG-7, pp.150, 1991. [2] M. Guth, Mater. Sci. Engineering C, 19, pp.129-133, 2002. [3] J. S. Moodera, Phys. Rev. Lett., 74, 3273, 1995. [4] Lohndorf M, Appl. Phys. Lett., 81, 313, 2002. [5] S. Ikeda, J. hayakawa, Y. M. Lee, R. Sasaki, T. Meguro, F. Matsukura and H. Ohno, Jpn. J. Appl. Phys., 44, pp.L1442-L1445, 2005 [6] N. Baibich, J. M. Broto, A. Fert, F. Nguyen Van Dau, F. Petroff, P. Creuzet, A. Friederich and J. Chazelas, Phys. Rev. Lett., 61, pp.2472-2475, 1988. [7] Bruce A. Gurney, Phys. Rev. Lett., 71, 4023, 1993. [8] B. Dieny, J. Magn. Magn. Mater., 93, 101, 1991. [9] J. C. S. Kools, IEEE Trans. Magn., 32, 3165, 1996. [10] R. Nakatani, Hiroyuki, K. Hoshino, S. Noguchi and Y. Sugita, Jpn. J. App. Phys., 34, 2312, 1995. [11] S. L. Burkett, S. Kora, J. L. Bresowar, J. C. Lusth, B. H. Pirkle and M. R. Parker, J. Appl. Phys., 81, 4912, 1997. [12] T. Lin, D. Mauri, N. Staud, C. Hwang, K. Howard and G. L. Gorman, Appl. Phys. Lett., 65, 1183, 1994. [13] K. Yagami, J. Appl. Phys., 89, 6609, 2001. [14] S. S. Parkin, Phys. Rev. Lett., 72, pp.3718, 1994. [15] William E. Bailey, Phys. Rev. B, 61, 1330, 2000. [16] H. Sakakima, J. Magn. Magn. Mater., L20-24, 210, 2000. [17] Y. Kamiguchi, IEEE conference, DB01, 1999. [18] B. Diney, P. Humbert, V. S. Speriosu, S. Metin, B. A. Gurney, P. Baumgart and H. Lefakis, Phys. Rev. B, 45, 806, 1992. [19] A. Vedyayev, B. Diney, N. Ryzhanova, J. B. Genin and C. Cowache, Europhy. Lett., 25, 465, 1994. [20] H. J. M. Swagten, Phys. Rev. B, 53, pp.9108, 1996. [21] M. Mao, J. Appl. Phys., 91, pp.8560, 2002. [22] T. Mizuguchi, IEEE Trans. Magn., 37, pp.1742, 2001. [23] K. Okada and T. Sekino, “Impedance Measurement Handbook”, Agilent Technologies Co. [24] M. F. Gillies, A. E. T. Kuiper, R. Coehoorn and J. J. T. M. Donkers, J. Appl. Phys., 88, pp.429-434, 2000. [25] H. Kaiju, S. Fujita, T. Morozumi and K. Shiiki, J. Appl. Phys., 91, pp.7430-7432, 2002. [26] K. T. M. Ranmuthu, I. W. Ranmuthu, A. V. Pohm. C. S. Comstock and M. Hassoun, IEEE Trans. Magn., 28, 5, 1992.
摘要: This paper is study the magneto impedance behaviors of pseudo spin valve (PSV) with nano-oxide layer (NOL) in annealing treatment and changing the area size. In magnetic multi-layer, the impedance was changed by the changing magnetic field H, and the equivalent relation is Z(H,f) = R(H,f) + iX(H,f), in which R is real part of impedance, X ( = XL - XC ) is imaginary part of impedance, f is frequency, XL and XC is contribution by the inductance and the capacitance. We joined the Co-NOL and Ni80Fe20-NOL in the top and bottom of the PSV main sandwich structure Co/Cu/Co/Ni80Fe20. The MR ratio increasing from 4.65% (without NOL) to 5.41% (with NOL). So we confirmed that joining the NOL in magnetic device can enhances the MR ratio effectively by means of specular scattering effect. Analyzing the impedance behaviors of NOL-PSV, we found that the stronger the magnetocapacitance effect in magnetic devices, the thicker the NOL. In the hysteresis loop, the imaginary part of impedance in antiparallel state is smaller than that in parallel state, that is Im(Z↑↓) < Im(Z↑↑). When the frequency is in the resonance frequency 683kHz, the Im(Z↑↑) closes to zero and makes the MX ratio has maximum value 18000%. In the impedance measurement of NOL-PSV with different annealing temperature and of PSV with different area, we saw that roll-off frequency ( froll ) has the law changing. When the annealing temperature increasing from room temperature to 200oC, froll increasing from 335kHz to 465kHz. When the area increasing from 20pm2 to 100pm2, froll decreasing from 900kHz to 65kHz. According to froll = 1/(2πRC), this result can explained by parallel board theory. Via this impedance spectroscopy, we could easily distinguish to NOL effects through a easy, fast, and non-destructive “qualitative” analysis. If we can investigate thin impedance spectroscopy to a “quantitative” analysis, it will be helpful to material analysis in structure in the future.
本論文是探討含有奈米氧化層( Nano-Oxide Layer, NOL )之類自旋閥( Pseudo Spin Valve, PSV )退火後及改變面積大小的磁阻抗行為關係。在磁性多層膜中,阻抗可隨著磁場H變化,其等效關係如Z(H,f) = R(H,f) + iX(H,f),R為阻抗實部,X ( = XL – XC )為阻抗虛部,f為頻率及XL與XC分別是電感與電容的供獻。 在PSV的主要三明治結構Co/Cu/Co/Ni80Fe20的上、下層分別加入了Co-NOL與Ni80Fe20-NOL兩種奈米氧化層,發現加入NOL後,MR值從原本未加入NOL的4.65%上升到了5.41%,證實在電子元件中加入的NOL在結構中造成鏡面反射效應,可有效地提升MR值。 分析Co-NOL/Co/Cu/Co/Ni80Fe20/Ni80Fe20-NOL的阻抗特性,發現該磁性元件中的電容效應會隨著NOL的厚度增加而增加,電容效應影響的阻抗虛部磁滯現象在平行態時(磁性層間的磁化方向相同)虛部阻抗比反平行態時(磁性層間的磁化方向相反)大,此一現象與其DC行為相反。當頻率大於共振頻率683kHz時,虛部磁阻抗值會從負值轉為正值,且在共振頻率時MX值高達將近18000%。 測量退火後與不同面積之PSV的阻抗特性時,可看到roll-off frequency有規律的變化;隨著退火溫度從室溫上升至200℃,roll-off frequency會從335kHz增加到465kHz,此結果可藉由公式froll=1/(2πRC)進一步推得樣品電容會隨著退火溫度的上升而變小,因為氧化層提供電容效應,所以此結果可以用平行電板理論C=εA/d解釋之;同樣地,當隨著PSV的面積從20pm2增加到100pm2,roll-off frequency會從900kHz下降至65kHz,此結果也與平行電板理論C=εA/d不謀而合。 此阻抗分析系統可”定性地”且非破壞性地檢測出奈米氧化層在結構中的影響,目前雖然測量樣品的DC行為也可達相同的論點,但若能進一步地研究出”定量地”阻抗分析系統,此技術對日後結構中材料分析會有很大的幫助。
URI: http://hdl.handle.net/11455/16991
其他識別: U0005-0108200714074600
文章連結: http://www.airitilibrary.com/Publication/alDetailedMesh1?DocID=U0005-0108200714074600
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