(3.238.186.43) 您好!臺灣時間:2021/03/02 09:38
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果

詳目顯示:::

我願授權國圖
: 
twitterline
研究生:劉學欣
研究生(外文):Liu Shiue Shin
論文名稱:用自由電子模型探討單位壘和雙位壘穿隧元件的磁阻效應
論文名稱(外文):A Free Electron Model Study of Magnetoresistance effect in Single and Double Barrier Tunneling Junction
指導教授:郭光宇郭光宇引用關係
指導教授(外文):G. Y. Guo
學位類別:碩士
校院名稱:國立臺灣大學
系所名稱:物理學研究所
學門:自然科學學門
學類:物理學類
論文種類:學術論文
論文出版年:1999
畢業學年度:87
語文別:英文
論文頁數:60
中文關鍵詞:磁阻雙位壘單位壘穿隧元件自旋電流源自旋極化
外文關鍵詞:Tunneling JunctionMagnetoresistanceSpin current sourceSpin valveDouble barrier junctionSpin filter
相關次數:
  • 被引用被引用:0
  • 點閱點閱:380
  • 評分評分:系統版面圖檔系統版面圖檔系統版面圖檔系統版面圖檔系統版面圖檔
  • 下載下載:0
  • 收藏至我的研究室書目清單書目收藏:0
我們利用轉換矩陣方法嚴格求解自由電子模型近似下的三維水丁格方程式,必據以計算單位壘和雙位壘磁性穿隧元件的電流自旋極化和磁阻效應。在單位壘元件的計算中,我們發現磁阻效應將隨偏壓增大而變小,在某些偏壓範圍甚至呈現負直,並隨偏壓變化有一震盪的關係。在雙位壘元件的研究中,我們發現共振穿隧能級扮演一個很重要的角色,適當的設計共振能級的位置可以達到最佳磁阻和自旋電流極化源的效果。

Current spin polarization and tunneling magnetoresistance (MR) of
single and double magnetic tunneling junctions have been calculated within the free electron model by solving rigorously the 3D Schrodinger equation for different bias voltages and barrier widths. For single barrier junction, it is found that in general, the MR would decrease with voltage and become negative at some large voltages, a trend in agreement with both earlier and recent experiments. Also, it is revealed that for certain barrier widths, the MR would oscillate with bias voltage which is a prediction to be confirmed by experiments. We also describe a principle for designing double barrier magnetic tunneling structure that could produce spin current with controllable spin direction or have optimal spin valve effect. The principle is based on the finding that by tuning the energy position of spin dependent resonant tunneling level of a double barrier junction, fully spin-polarized current and optimal MR effect could be
readily achieved.

Contents
1 Introduction
2 Model and Method
2.0 The model
2.1 Transfer Matrix Method
2.2 Interpretation of M matrix
2.3 Current integration
3 Single Barrier TMR
3.1 Transmission Coefficient - Dispersion Relation
3.2 Current Plot and TMR Analysis
4 Double Barrier TMR
4.1 Configuration of Magnetization Axes
4.2 Spin Valve
4.3 Spin current source
4.3.1 Type I: NM/Is/Ic/FM/Ic/Is/NM structure
4.3.2 Type II: S/I/FM/I/S structure
5. Summary and Disscussion
References

References
1. J.S. Moodera, Lisa R. Kinder, Terrilyn M. Wong, and R. Meservey, Phys. Rev. Lett., 74, 3273, (1995).
2. J. S. Moodera and Lisa R. Kinder, J. Appl. Phy., 79, 4724 (1996).
3. M. Julliere, Phys. Lett., 54A, 225 (1975).
4. J. C. Slonczewski, Phys. Rev., B 39, 6995 (1989).
5. T Miyazaki, et. al., J. Phys. D: Apply. Phys. 31, 630 (1998).
6. Manish Sharma, et. al., Phys. Rev. Lett., 82, 616 (1999).
7. A. Voskoboynikov, et. al., Phys. Rev. B, (1999).
8. V. V. Paranjape, Phys. Rev. B 52, 10740 (1995)..
9. Xiangdong Zhang, et al., Phys. Rev. B 56, 5484 (1997).
10. S. T. Chui, Phys. Rev. B 55, 5600 (1997)
11. A. M. Bratkovsky. Phys. Rev. B 56, 2344 (1997)..
12. J. S. Moodera, et al. Phys. Rev. Lett. 70, 853 (1993).
13. Mary Beth STEARNS, J. Mag. Mag. Material 5 167 (1977)
14. Principles of Electron Tunneling Spectroscopy, E.L. Wolf (Oxford, Oxfordshire, 1985)
15. Handbook of Mathematical Functions, edited by M. Abramowittz and I. A. Stegun (Dover, New York, 1965).
16. X. Hao, et al., Phys. Rev. B 42, 8235 (1990).
17. J. L. Simonds, Physics Today, Apiral, 26 (1995)

QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top
系統版面圖檔 系統版面圖檔