基于Ni-Mn-Sn磁性记忆合金薄膜的太赫兹波调控研究

太赫兹技术在生物成像、高灵敏传感和高速通信等领域有着重要的应用前景，然而缺乏高性能的太赫兹调控功能器件是制约其发展的主要瓶颈。本项目提出利用Ni-Mn-Sn磁性记忆合金薄膜在外磁场作用下，其介电性质和材料形状同时可调的特点，开发高性能的太赫兹功能器件的新思路。本项目拟从Ni-Mn-Sn薄膜设计与制备入手，研究制备工艺对薄膜成分均匀性及表面形貌的影响规律，制备马氏体相变温度位于室温的高质量薄膜；研究母相与马氏体相的太赫兹特性，阐明马氏体相变对太赫兹性能的调控规律及微观机制；研究磁场作用下马氏体相变行为及其对薄膜太赫兹性能的影响规律，揭示磁场对薄膜太赫兹性能的调控规律及机制；设计和制备基于Ni-Mn-Sn薄膜的超材料器件，阐明器件结构与太赫兹调控性能的内在联系，确定获得高性能Ni-Mn-Sn薄膜太赫兹超材料功能器件的设计准则及制备工艺，为发展新型高性能太赫兹主动控制功能器件奠定基础。

Terahertz (THz) technology has attracted considerable attention due to its potential in the field such as bioimaging, high-sensitive sensing and high-speed communication. However, the lack of high performance THz modulation device is the main bottleneck currently. In this project, the new idea for developing the new THz functional device with high performance is proposed. It is mainly dependent on that the dielectric properties and shape of Ni-Mn-Sn magnetic shape memory alloy thin films can be controlled and modulated under an extra magnetic field. Ni-Mn-Sn alloy thin films are designed and prepared. Then the influence of the fabrication technique on the uniformity and surface morphology of the thin films is investigated to obtain the principle for designing the uniformity and surface smoothness thin films with the martensitic transformation temperature near the room temperature. Based on that, then the THz properties of the martensite and austenite of Ni-Mn-Sn alloy films are studied. The effect of the martensitic transformation on the THz properties and its mechanism are explained. Moreover, the martensitic transformation behavior under magnetic field and its influence on the THz properties are investigated, to reveal the modulation and its mechanism of magnetic field on THz properties of thin films. Furthermore, the metamaterials devices based on Ni-Mn-Sn alloy thin films are designed and prepared, and the internal relationships between the structure of device and the modulation of THz properties are illustrated. Finally, the principle for design and fabrication technique of high performance THz metamaterials functional device based on Ni-Mn-Sn alloy thin film are presented. The research mentioned above provide theoretical guidance for developing the new THz active control functional device.