- 學位論文
雙層勢壘磁性穿隧接面之自旋轉移力矩
Spin Transfer Torque in Magnetic Tunneling Junctions with Double Barriers
摘要
本文主旨為研究單層勢壘結構與雙層勢壘結構下磁性穿隧接面內自旋轉移力矩的特性，透過改變材料的參數與施加的偏壓，包含了勢壘厚度、位能、自旋分裂能量與外加電壓等變化，並討論其穿隧電流以及自旋轉移力矩大小的影響，而自旋轉移力矩是一種利用自旋極化電流使磁矩翻轉之現象，本研究也將描述自旋轉移力矩的性質。本論文將使用自由電子模型以及轉移矩陣法來描述電子的行為，並推導磁性穿隧接面內的自旋流密度，進而獲得自旋轉移力矩。接著將討論單層勢壘結構與雙層勢壘結構下，共振效應的影響。由於自旋轉移力矩現象為現今元件中改變磁阻大小最有效率的方式，因此本論文研究有助於提升磁性穿隧接面的性能，使其達到低消耗高輸出的效果。
並列摘要
Properties of spin-transfer torque in magnetic tunnel junction with single and double barriers are studied. In the beginning, free electron model is used to construct the basic properties of the transfer of spin current density. The spin current density in magnetic tunnel junction is calculated by using transfer matrix method. After the model has been discussed, the parameter of the magnetic tunnel junction will be adjusted, and the numerical results show that the tunnel current density and spin-transfer torque are a function of angle between magnetic moments, barrier height, thickness, spin splitting energy and voltage. Eventually, the contrast between the structure with single barrier and double barriers will be discussed. Due to the resonant effect in the magnetic tunnel junction with double barriers, the results theoretically show that the tunnel current density as well as the spin-transfer torque through the system can be drastically increased.
參考文獻
延伸閱讀
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