| 自旋阀结构中自旋转移矩效应驱动磁化 |
| Alternative Title | Spin-transfer torque-induced magnetization in spin valve
|
| 夏海艳 |
| Thesis Advisor | 王建波
|
| 2012-05-27
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| Degree Grantor | 兰州大学
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| Place of Conferral | 兰州
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| Degree Name | 硕士
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| Keyword | 自旋转移矩
生物传感器
微磁学模拟
铁氧体
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| Abstract | 自1996年理论预言自旋转移矩(spin transfer torque, STT)效应受到人们的广泛关注。STT效应可驱动磁矩翻转或者激发自由层磁矩振荡，从而可以应用于高密度磁性随机存储器(MRAM)以及高频发生器(spin torque oscillator)。本论文针对自旋转移矩开展了两方面的研究工作，主要内容如下：
首先，我们设计并研究了自旋振荡生物传感器。利用自旋振荡器的振荡频率对外磁场的良好线性关系，该磁性传感器通过振荡频率的移动可以探测磁性颗粒的杂散场，从而可以探测磁性颗粒标记的生物分子。这种方法为分子识别，药物诊断等提供新的探测工具。微磁学模拟结果显示：直径为40纳米的磁性颗粒可以使自旋振荡器产生0.26 GHz频率移动。磁性颗粒的尺寸，位置以及个数对自旋振荡器的振荡频率都有影响。
其次，我们模拟了在自旋阀结构中静磁场辅助自旋转移矩效应诱导磁矩翻转。模拟显示在水平静磁场辅助下，其临界电流密度和翻转时间都下降了50%，为MRAM的实际应用提供了理论基础。 |
| Other Abstract | Spin transfer torque (STT) effect has attracted considerable attention since the prediction in 1996. STT can introduce magnetization switch or excite magnetization oscillations, thereby possess applications in high-density MRAM and microwave generation. In this study, two parts of work focused on STT had been investigated. The content is as follows.
Firstly, we designed and investigated a spin torque oscillation biosensor. Using the good linear response to magnetic field, the sensor can detect the stray field of magnetic particles via frequency shift, thereby detecting molecules labeled with magnetic particles and providing method for molecules recognition and biomedicine diagnostic. Simulations demonstrated that a 40-nm-diameter particle can be detected with a frequency shift of 0.26 GHz. The dependence on the size, position and number of particles was also investigated.
Secondly, we simulated STT-induced magnetization switch assisted by static magnetic field in a spin valve. Simulations demonstrated critical current density and switching time can reduce 50% due to magnetic field, providing theory foundation for application in MRAM. |
| URL | 查看原文
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| Language | 中文
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| Document Type | 学位论文
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| Identifier | https://ir.lzu.edu.cn/handle/262010/228986
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| Collection | 物理科学与技术学院
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Recommended Citation
GB/T 7714 |
夏海艳. 自旋阀结构中自旋转移矩效应驱动磁化[D]. 兰州. 兰州大学,2012.
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