平面Z型六角铁氧体薄膜GHz高频磁性研究

Since the modern high-frequency micro-devices are increasingly miniaturized and integrated, magnetic materials with large permeability in the GHz range are urgently needed. Co2Z-type planar hexaferrite is an excellent high-frequency magnetic material. Furthermore, the latest research results show that films have better high-frequency magnetic properties than normal bulks. Therefore, this proposal addresses the problem of how to control the magnetic anisotropy of Co2Z-type planar hexaferrite films utilizing films having strong shape anisotropy, and then how to prepare ferrite films with large permeability in the GHz range. Our proposal focus on: 1. Co2Z-type planar hexaferrite films are to be fabricated by radio-frequency magnetron sputtering, and their structural and morphological characteristics are to be measured. 2. The macroscopical and microscopical magnetic properties of the ferrite films are to be measured and analyzed, especially the characteristic of magnetization distribution and magnetic anisotropy. Besides, the complex permeability of the ferrite films are to be measured by vector network analyzer using shorted microstrip transmission-line perturbation method, and the natural resonance frequency and dynamic permeability would be obtained from the complex permeability spectrums. 3. By analyzing the experimental data and theory simulation, the experimental technology of controlling and adjusting the natural resonance frequency and permeability of Co2Z-type planar hexaferrite films would be grasped, and the mechanism of the ferrite films with high natural resonance frequency and large dynamic permeability would be known. This program will not only get Co2Z-type planar hexaferrite films with high natural resonance frequency and large dynamic permeability in the GHz range, but also provide the theoretical and technical basis for their application in high-frequency micro-devices.

现代高频器件微型化与集成化迫切需要在GHz频段具有高磁导率的材料。Co2Z平面型六角铁氧体是一种良好的高频磁性材料。同时，研究表明磁性材料薄膜化后可以极大提高其高频特性。因此，本项目以获得GHz频段具有高磁导率的Co2Z平面型六角铁氧体薄膜为目的,以利用薄膜具有强的形状各向异性来实现对铁氧体薄膜磁各向异性的调控为关键展开研究。重点研究：1.采用射频磁控溅射法制备Co2Z铁氧体薄膜，掌握不同厚度、晶粒尺寸和结构取向的薄膜制备工艺；2.通过宏观和微观磁性测量，分析薄膜的内禀和技术磁性,尤其是磁化强度的分布和磁各向异性特征，并利用矢量网络分析仪测量分析薄膜的高频磁性；3.综合实验和理论模拟结果，掌握调控Co2Z铁氧体薄膜磁特性的方法，分析其高共振频率和高磁导率的机制。该研究不仅可以获得高频下具有高磁导率的Co2Z铁氧体薄膜，而且将为其在高频微器件中的应用提供理论和技术依据。

现代高频器件微型化与集成化迫切需要在GHz频段具有高磁导率的薄膜材料。本项目以获得共振频率在GHz频段同时具有高磁导率的Co2Z平面型六角铁氧体薄膜为目的，通过利用薄膜具有强形状各向异性来实现对铁氧体薄膜各向异性调控为关键开展研究内容。首先利用溶胶-凝胶法制备了具有高共振频率和磁导率的Co2Z铁氧体颗粒，研究了平面型六角铁氧体的共振机制；利用磁控溅射和高温热后处理制备Co2Z铁氧体薄膜，结合成分、结构、形貌和磁性能等测试，掌握了制备较好结晶，高饱和磁化强度，低矫顽力的铁氧体薄膜最佳制备条件；利用微带线法和矢量网络分析仪测量和分析了薄膜的高频磁性，得到了共振频率在GHz频段，同时具有高的初始磁导率（约20）的铁氧体薄膜，并对其物理机制进行了研究。该研究内容和成果将为材料在高频器件中的实际应用提供了理论和技术支持，达到了项目的预期研究目标。