二维Fe_(5)GeTe_(2)单晶的大量制备及吸波性能研究

Mass Preparation and Microwave Absorption Performance of Two-dimensional Fe_(5)GeTe_(2)Single Crystals

目的快速制备克量级、高质量的二维磁性Fe_(5)GeTe_(2)单晶,并开发具有范德华结构、室温铁磁性及优异微波吸收性能的新型吸波材料。方法通过调控输运剂的含量,并缩短化学气相传输法的恒温段时长,以探索高质量Fe_(5)GeTe_(2)单晶的快速、制备量大的方法。将Fe_(5)GeTe_(2)单晶与石蜡按不同质量分数混合后,通过同轴线测试法分析其微波性能。结果成功制备了克量级、高质量的Fe_(5)GeTe_(2)单晶样品。借助矢量分析仪的同轴线测试法研究Fe_(5)GeTe_(2)单晶的微波损耗性能发现,当Fe_(5)GeTe_(2)的质量分数为30%时,Fe_(5)GeTe_(2)的吸波特性较差,最佳反射损耗值仅为−4.8 dB;当Fe_(5)GeTe_(2)的质量分数达到70%时,Fe_(5)GeTe_(2)载荷的增加导致界面极化增强,并改善了阻抗匹配。电磁波顺利进入吸波剂内部,并以介电损耗和磁损耗的形式耗散掉,吸波性能得到极大提升,最佳反射损耗值达到了−35.5 dB。结论成功制备了克量级、高质量Fe_(5)GeTe_(2)单晶样品,为该二维磁性材料的基础物性研究提供了一个良好的物质基础,其优异的微波吸收特性归因于良好的阻抗匹配和多种损耗机制的协同作用。具有室温磁性的Fe_(5)GeTe_(2)是一种具有优异性能的新型吸波材料,也为复合吸波剂的研究提供了多种选择。

The work aims to rapidly prepare gram-scale,high-quality two-dimensional magnetic Fe_(5)GeTe_(2)single crystals and develop new absorbing materials with van der Waals structure,room-temperature ferromagnetism,and excellent microwave absorption performance.In this work,Fe_(5)GeTe_(2)single crystal samples were synthesized by adjusting the content of transport agents and shortening the constant temperature period of chemical vapor transport method.Fe_(5)GeTe_(2)single crystals were mixed with paraffin wax according to different mass fractions.Their microwave absorption performance was analyzed by a coaxial line test.Gram-scale,high-quality Fe_(5)GeTe_(2)single crystal samples were prepared successfully.The microwave absorption performance of Fe_(5)GeTe_(2)single crystals was analyzed by the coaxial wire method with a vector network analyzer.The results indicated that the absorption performance of 30%Fe_(5)GeTe_(2)was poor,and the minimum reflection loss value was only−4.8 dB.However,as the mass fraction of Fe_(5)GeTe_(2)increased to 70%,the enhanced Fe_(5)GeTe_(2)load in the Fe_(5)GeTe_(2)/paraffin composites led to improved interface polarization and enhanced impedance matching.The electromagnetic wave could smoothly penetrate the Fe_(5)GeTe_(2)/paraffin composites and then be dissipated via dielectric loss and magnetic loss,significantly enhancing its absorption performance.The minimum reflection loss value could reach−35.5 dB.The successful synthesis of gram-scale high-quality Fe_(5)GeTe_(2)single crystals establishes a solid material foundation for researching the fundamental physical properties of this two-dimensional ferromagnet.Additionally,Fe_(5)GeTe_(2)with room-temperature magnetic properties is not only a new type of absorbing material with excellent performance,but also provides a new choice for the research of composite absorbing agents.