兰州大学机构库 >物理科学与技术学院
铁磁薄膜中铁磁共振和自旋激发的自旋整流研究
Alternative TitleStudy on ferromagnetic resonance and spin excitations in ferromagnetic thin film by spin rectification
张艺超
Thesis Advisor杨德政 ; 范小龙
2016-05-29
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword自旋整流 铁磁共振 自旋激发 角度依赖
Abstract本论文系统地研究了磁性薄膜中铁磁共振和自旋激发等高频特性。与铁磁共振等传统高频测量方法不同,本文主要采用自旋整流效应,即利用磁性薄膜被微波激发时磁矩进动产生直流电压来观测样品中的铁磁共振和自旋激发模式。通过改变外加磁场幅度及与样品之间的夹角,我们可以很清晰地观测到铁磁共振和自旋激发模式,同时测量共振位置和线宽随角度的变化,得到磁性薄膜相应的高频参数和自旋激发的模指数等。本文基于自旋整流效应,详细地研究了铁磁薄膜中的铁磁共振和自旋激发,对自旋器件的未来发展和设计高速、高密度的磁性存储器具有重要的意义。具体的研究工作有: 1. 推导出外加磁场位于薄膜面外时铁磁共振和自旋激发的角依赖的色散关系及磁化强度在平衡位置下和外磁场的角度约束关系。基于上述色散关系和角度约束关系,可以得到铁磁共振和自旋激发的共振位置随外场方向的变化关系。 2. 基于平面霍尔自旋整流效应,本文系统地研究了Fe19Ni81微米条带中的铁磁共振和自旋激发模式。利用上述推导关系式对测量得到的外加磁场位于薄膜面外时铁磁共振和自旋激发的共振位置随着外场角度的变化关系进行拟合,得到了材料的高频参数和自旋激发的模指数。与利用传统色散的方法测量得到的高频参数相比较,发现两组参数符合的非常好,进而验证了基于自旋整流效应的角依赖的方法研究铁磁共振和自旋激发的准确性。 3. 基于角度依赖的研究方法,研究了形状对铁磁共振和自旋激发的影响。通过对三个样品(条形样品、串联点阵样品、单点子样品)的自旋整流谱线进行拟合,可以得到相应的高频参数及线宽随外场方向的变化关系,进而得到形状对饱和磁化强度、自旋驻波的边界条件和线宽的影响。
Other AbstractIn this dissertation, we comprehensively study ferromagnetic resonance and spin excitations in ferromagnetic thin film based on spin rectification. By changing the angle of applied magnetic field with respect to the film normal, high angular resolution spin rectification spectra for a single Permalloy micro-strip are obtained. The ferromagnetic resonance, perpendicular standing spin wave, and magnetostatic modes can be directly visualized in those mappings and the angular evolution of each resonance mode can be clearly observed. By fitting the angular evolution of each resonance peak in the mappings, the dynamic parameters of each mode and the quantized numbers of standing spin waves can be acutely determined. This dissertation comprehensively study ferromagnetic resonance and spin excitations in ferromagnetic thin film by spin rectification, is an important issue for the further development of spin devices and designing high density magnetic memories with fast recording speed. This dissertation mainly includes the following: 1. Near the film normal, the angular dependent dispersion relationships of FMR and spin excitations are proposed, and the angular constrained relationship of magnetization and applied magnetic field is gotten. Then the FMR, PSSWs, and MSFVMs resonance position curves are gotten by solving the angular dependent dispersion relationships and the angular constrained relationship of magnetization and applied magnetic field. What above is the principle of angular dependent dc electrical approach. 2. To prove accuracy of the angular dependent approach, we study FMR and spin excitations in single Permalloy stripe based on planar Hall effect, and get 2D color mappings of angular resolution spin rectification spectra at different frequencies. Base the equations we get above, we fit the FMR and spin excitations curves, and the agreement of the fitting results for the FMR and PSSWs with the measured curves is excellent, which allows us to identify these modes and accurately determine the values of dynamic parameters. Compared to the traditional approach for studying spin excitations, the results are self-consistent, so the angular dependent approach is correct. 3. By the angular dependent approach, we study the effect of structure on ferromagnetic resonance and spin excitations by spin rectification. By fitting the measurend results of three different sample (micro-strip, dot array and a dot), we can get he values of dynamic parameters and the ...
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229284
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
张艺超. 铁磁薄膜中铁磁共振和自旋激发的自旋整流研究[D]. 兰州. 兰州大学,2016.
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