共面波导测试磁性薄膜微波磁性能

发布时间：2018-06-20 19:42

本文选题：磁导率频谱 + 共面波导　；参考：《电子科技大学》2014年硕士论文

【摘要】：伴随着现代科学技术的迅速发展,利用磁性薄膜材料设计和制备的高性能磁性器件具有尺寸小、精度高以及速度快等特点,广泛地应用在微机电系统、微波通讯系统、电子对抗系统和信息存储系统等领域。随着电子器件工作频率的提高,磁性薄膜大量地应用在微波频段,准确地表征磁性材料的微波电磁参数如微波磁导率以及铁磁共振线宽不仅是其应用的基础,同时也是研究磁性薄膜高频磁化动力学的基础。因而准确表征磁性薄膜的微波磁性能(主要包括微波磁导率和铁磁共振线宽)具有十分重要的意义。论文首先建立了利用共面波导传输线来测试薄膜磁导率的计算模型,根据传输线的集总电路模型结合微波网络散射参数推导了利用测试得到的散射参数来计算磁性薄膜微波磁导率频谱的公式。然后设计了共面波导测试夹具,并对其尺寸进行了仿真优化,确定接地共面波导(GCPW)测试夹具尺寸为:基片材料选用厚度为0.508mm的Roggers5880,GCPW的中间信号导带宽度为1.2mm,信号导带与两边接地板的间距为0.1mm。对加载了磁性薄膜的测试夹具的仿真计算结果表明,计算出的磁谱与仿真时输入磁谱基本一致。利用GCPW夹具测试了各向同性NiFe膜、各向异性NiFe薄膜以及倾斜溅射制备的NiFe膜的磁谱,并用理论磁谱公式进行了拟合。结果表明所有NiFe薄膜测试计算出的磁谱均可以用理论公式进行很好的拟合,验证了该测试夹具以及测试理论的正确性。测试结果表明,各向同性NiFe膜的共振频率为0.9GHz,拟合得到的饱和磁化强度sM?686 kA m,各向异性场kH=0.608 kA m,阻尼系数?=0.0 2。各向异性NiFe膜共振频率为2GHz,sM?495 kA m,kH=5.2 kA m,阻尼因子?=0.02。倾斜溅射制备的普通NiFe膜共振频率为2.2GHz,sM?724 kA m,kH=5.6 kA m,阻尼因子?=0.012。利用铁磁共振过程中磁性薄膜吸收能量与外加磁场的关系建立了利用共面波导测试夹具来测试磁性薄膜铁磁共振线宽的方法。用GCPW夹具测试了普通NiFe膜和加热条件镀的NiFe膜铁磁共振频率随外磁场的变化,结果表明,共振频率随着外加稳恒磁场的增大向高频移动。普通NiFe薄膜在3GHz、3.5GHz、4GHz频率下的铁磁共振线宽分别为41.7Oe、45.9Oe、50.4Oe而加热条件下制备的NiFe膜在3GHz、3.5GHz、4GHz频率下的的铁磁共振线宽分别为90Oe、100.3Oe、110.2Oe。
[Abstract]:With the rapid development of modern science and technology, the high performance magnetic devices designed and fabricated by using magnetic thin film materials have the characteristics of small size, high precision and high speed. They are widely used in MEMS and microwave communication systems. Electronic countermeasures systems and information storage systems and other areas. With the increasing of the working frequency of electronic devices, magnetic thin films are widely used in microwave frequency band. It is not only the basis of their application to accurately characterize the microwave electromagnetic parameters of magnetic materials such as microwave permeability and ferromagnetic resonance linewidth. At the same time, it is the basis of studying the high frequency magnetization kinetics of magnetic thin films. Therefore, it is of great significance to accurately characterize the microwave magnetic properties of magnetic films (including microwave permeability and ferromagnetic resonance linewidth). In this paper, a calculation model for measuring the permeability of thin films using coplanar waveguide transmission lines is established. Based on the lumped circuit model of transmission line and the scattering parameters of microwave network, the formula for calculating the microwave permeability spectrum of magnetic thin films is derived by using the measured scattering parameters. Then the coplanar waveguide testing fixture is designed and its size is simulated and optimized. The size of the test fixture is determined as follows: the width of intermediate signal conduction band of Rogers 5880 GCPW with thickness of 0.508mm is 1.2 mm, and the distance between the signal conduction band and the floor connected to both sides is 0.1 mm.. The simulation results of the test fixture loaded with magnetic film show that the calculated magnetic spectrum is basically consistent with the input magnetic spectrum in the simulation. The magnetic spectra of isotropic nife films, anisotropic nife films and nife films prepared by tilt sputtering were measured by GCPW clamp. The results show that all the magnetic spectra of nife films can be fitted well by theoretical formula, and the correctness of the testing fixture and testing theory is verified. The results show that the resonance frequency of the isotropic nife film is 0.9GHz, the saturation magnetization (sm) is 686kA / m, the anisotropic field is 0.608kA / m, and the damping coefficient is 0.02. The resonance frequency of the anisotropic nife film is 2 GHz / m ~ (495) KH ~ (5. 2) KH ~ (2 +), and the damping factor is 0. 02. The resonance frequency of ordinary nife films prepared by inclined sputtering is 2.2GHz / s Mn 724kA / KH ~ + 5.6 kA / m, and the damping factor is 0.012 / m. Based on the relationship between the absorption energy of magnetic thin films and the applied magnetic field in ferromagnetic resonance, a method for measuring the linewidth of magnetic thin films using coplanar waveguide testing fixture is established. The change of ferromagnetic resonance frequency with external magnetic field of ordinary nife film and nife film deposited under heating condition was measured by GCPW clamp. The results show that the resonance frequency moves to high frequency with the increase of external steady magnetic field. The ferromagnetic resonance linewidths of ordinary nife thin films at the frequency of 3 GHz and 3.5 GHz are 41.7 OeN 45.9 Oe and 50.4 Oe, respectively, and the ferromagnetic resonance linewidth of the nife films prepared at 3GHz 3.5GHz is 90Oe100.3Oe110.2Oerespectively.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN814

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