| 外延生长铁单晶薄膜的高频磁性 |
| Alternative Title | High-frequency magnetic properties of epitaxial Fe single crystal films
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| 王昱天 |
| Thesis Advisor | 薛德胜
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| 2016-05-29
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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 | 高频特性
磁各向异性
单晶Fe薄膜
外延生长
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| Abstract | 目前高频磁性薄膜以多晶薄膜为主，不仅无法体现磁晶各向异性的优势，且无法定量地验证高频理论模型。基于单晶磁性薄膜在高频磁性研究中的价值，我们提出了以单晶磁性薄膜为载体研究高频磁性的思路。在本文中，外延生长了具有不同参数的单晶Fe薄膜样品，测量了不同薄膜参数对样品磁性的影响，并结合理论分析了外延单晶薄膜的高频磁性。获得的主要结果包括：
（1）提出了立方晶系Fe单晶薄膜晶体取向的倾斜将在薄膜面内诱发单轴各向异性。制备了不同晶向倾角的Fe单晶薄膜样品，测试了每个样品的静态磁性；从理论上分析并计算了不同晶向倾角样品的面内各向异性常数；通过实验结果和计算结果的比对，证明了Fe单晶薄膜的晶向倾斜可诱发面内单轴各向异性。
（2）提出了利用Fe单晶薄膜的磁晶各向异性可获得面内“各向同性”的高频性能。通过Fe单晶薄膜的转角度磁谱测试，确定了样品可以在薄膜平面的不同方向上保持高于8 GHz的自然共振频率和大于50的高频磁导率；通过对剩磁状态的分析，证明了这种“各向同性”的性能源于四重各向异性下样品磁矩的非一致排列。
（3）提出并证实了通过改变晶体取向和薄膜厚度可以将Fe单晶薄膜的自然共振频率提高至10 GHz以上。并结合高频理论讨论了薄膜参数影响自然共振频率的机制。验证了通过改变外加直流磁场，不仅可以改变外延单晶Fe薄膜的共振频率，还可以在特定频率的外加交变磁场下，形成无共振、单共振和双共振三种模式。 |
| Other Abstract | Currently, the most of magnetic films working in high frequency are polycrystalline, which result in not only difficulty to take advantage of magnetocrystalline anisotropy, but also disability of proving theory quantitatively. Therefore, single crystal magnetic thin films are found to be significant candidate in studying high frequency properties. In this work, epitaxial single crystal Fe films with different parameters were grown for studying magnetic properties, and the discussed of these magnetic properties were made by theory of high frequency. The main results are shown as followed.
(1)We presented the mechanism that an in-plane uniaxial anisotropy can be induced by the tilt of crystal orientation in cubic single crystal Fe films. Single crystal Fe films with different tilt angle were grown by molecular beam epitaxy, and experimental study of static magnetics was carried out on these films. The in-plane anisotropy constants with different tilt angle were calculated by theory. Based on comparative analysis of experiment and calculation results, it was demonstrated that the tilt of crystal orientation can induce an in-plane uniaxial anisotropy.
(2)We found out the multidirectional available high frequency response, which can be induced by magnetocrystalline anisotropy in single crystal Fe films. With rotational measurement of magnetic spectrum, it was demonstrated that high resonance frequency above 8GHz and permeability above 50 can be reached with the microwave along different in-plane directions. By analyzing the remanence state, this multidirectional available characteristics is proved depending on non-uniform arrangement of magnetic moment.
(3)We proposed and verified that the resonance frequency can be raised above 10 GHz by adjusting crystal orientation and thickness of the single crystal Fe films. The mechanism of the adjustment was discussed by high frequency theory. It was demonstrated that applied magnetic field with contrivable strength and direction can not only adjust resonance frequency, but also transform the resonance mode among no-resonance, single-resonance and double-resonance. |
| 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/262010/229238
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| Collection | 物理科学与技术学院
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Recommended Citation
GB/T 7714 |
王昱天. 外延生长铁单晶薄膜的高频磁性[D]. 兰州. 兰州大学,2016.
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