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研究生： 陳小芳
Siow-Fang Chen
論文名稱： 巨磁阻結構中感應磁化之理論研究
The induced magnetization in the GMR sandwich structure
指導教授： 牟中瑜
Chung-Yu Mou
口試委員:
學位類別： 碩士
Master
系所名稱： 理學院 - 物理學系
Department of Physics
論文出版年： 2003
畢業學年度： 91
語文別： 英文
論文頁數： 59
中文關鍵詞： 巨磁阻 、量子阱
相關次數： 點閱：2  下載：0 
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    • 我們探討在巨磁阻結構裡中間層感應磁化的現象。在此，主要討論的是當兩層鐵磁層的磁化方向是平行時，同時並引入一交換耦和常數J於中間層，推導出中間層感應磁化量所遵循的自洽方程式。基於此自洽方程式，中間層的感應磁化量強度即可被決定，同時此感應磁化量也會影響兩層鐵磁層間的交換耦合能。我們發現感應磁化量會隨著中間層厚度變化而呈振盪的行為，其振盪的行為有一定的周期。隨著中間層厚度增加時，感應磁化量會急遽衰減至零，因此我們定義了一個有效衰減常數 ，經由改變系統的參數值來討論衰減常數的變化。

    We investigate the induced magnetization of the spacer layer in
    the magnetic quantum well of the GMR structure. Only parallel

    arrangements of the magnetization are considered. By assuming a

    non-vanishing exchange coupling constant in the spacer layer, we derive a self-consistent equation for the average induced

    magnetization. Based on the self-consistent equation, the induced magnetization is computed numerically, which then determines the coupling energies. The magnetization is found to oscillate with the width of the spacer layer. Furthermore, it shows distinct jumps with characteristic periods. At large d, the magnetization decays to zero rapidly, allowing one to define an effective decay length. Systematic studies of the dependence of decay length on the relevant parameters are performed.

    1 Introduction 1 2 Induced magnetization in the GMR sandwich structure 7 2.1 Magnetic quantum well 7 2.2 Self-consistent magnetization 14 2.2.1 Magnetization due to the bound states 14 2.2.2 Magnetization due to the scattering states 16 2.2.3 Self-consistent Equation 20 2.3 Numerical results 21 2.3.1 Self-consistent magnetization 21 2.3.2 Semi-infinite structure 29 2.3.3 For a case with an applied external field 31 2.3.4 Effective decay length 36 2.3.5 Oscillatory energy density 39 3 Future work and Outlook 44 A Other Configuration 46 A.1 relative angle between magnetic vectors 46 A.2 Spin Density Wave 49 A.3 Degeneracy 53 B Bound states in a conventional potential well 55 C Solutions for antiparallel case 57 D Effect of the scattering phase 59

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