太赫兹波段反铁磁自旋泵浦效应的研究

Spin pumping is a method of generating spin current, which is one of the most popular issues in spintronics. Spin pumping effect has been found in ferromagnet(ferrimagnet)/nonmagnet bilayers. Recently it was also predicted to exist in antiferromagnet/nonmagnet systems, however, no experimental evidence has been reported. In this project, we plan to study antiferromagnetic spin pumping effect experimentally in the THz regime. A measurement system for antiferromagnetic resonance (AFMR) spectra and spin-transport will be built utilizing THz vector network analyzer and high power THz source, etc. Coplanar waveguide and quasi-optical methods will be employed in the experiments measuring the enhanced AFMR linewidth and the inverse spin Hall voltage. The experiments in this project aims to confirm the antiferromagnetic spin pumping effect, and to give a better understanding on the spin current generation mechanism. Rich experience has been accumulated in long-term pre-study of ferromagnetic spin pumping, which ensures the proceeding of this project. The confirmation of antiferromagnetic spin pumping will not only fertilize the field of antiferromagnetic spintronics, but also promote the progress of THz technology.

自旋泵浦效应作为一种产生自旋流的方法，是目前自旋电子学的研究热点。自旋泵浦效应存在于铁磁/非磁、亚铁磁/非磁体系；理论预言反铁磁/非磁体系中也存在此效应，但还未被实验证实。本项目拟在太赫兹波段开展反铁磁自旋泵浦效应的研究。基于太赫兹矢量网络分析仪、高功率太赫兹源等建立反铁磁共振谱测量和自旋输运测量装置；利用共面波导和准光方法，获得反铁磁/非磁样品的共振线宽展宽、反自旋霍尔电压，从而实验验证反铁磁自旋泵浦效应，理解和揭示自旋流的产生机理。本项目组在铁磁自旋泵浦方面积累了良好基础和丰富经验，具备开展工作的软硬件条件，期望在此项目上获得进展，丰富反铁磁自旋电子学的内涵，同时也促进太赫兹技术的研究。

自旋泵浦效应作为一种产生自旋流的方法，是目前自旋电子学的研究热点。本项目在太赫兹波段开展反铁磁自旋泵浦效应的实验研究，同时研究了基于超快自旋流泵浦注入的自旋太赫兹源的性能提升方法。本项目制备获得反铁磁/重金属异质结（YFeO3/Pt）样品，利用建立的太赫兹波段反铁磁共振谱测量装置，通过太赫兹准光方法激发了反铁磁共振，并观测到反铁磁共振频率的太赫兹发射。本项目提出一种金属—介质光子晶体结构，解决了现有自旋太赫兹源对泵浦飞秒激光吸收率限制的问题，将太赫兹产生效率提升到原来的1.7倍，可直接替换商用ZnTe晶体用于太赫兹时域光谱仪系统中；将自旋太赫兹源与超材料相结合，在同一器件上实现了任意偏振态的太赫兹波产生；这两个成果将光学思想引入自旋太赫兹源的研究中，为其性能提升提供了新途径。在项目实施过程中，共发表SCI论文3篇，包括Advanced Optical Materials、Science Advances、Applied Physics Letters各1篇；获授权国家发明专利1项，获受理国家发明专利3项；在自旋量子态调控青年科技论坛等国内会议上做邀请报告3个，在IcAUMS等国际会议上做口头报告2个。