Insights into the micro magnetic loss mechanism of microwave absorption by off-axis electron holography
Insights into the micro magnetic loss mechanism of microwave absorption by off-axis electron holography
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DOI：
10.1016/j.jmmm.2018.11.045
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发表时间：
2019-04-01
影响因子：
2.7
通讯作者：
Che, Renchao
中科院分区：
文献类型：
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作者：
Lu, Yichao;You, Wenbin;Che, Renchao
高磁导率和高饱和磁化强度是磁性损耗复合材料具有强吸波性能的两个关键特征，这取决于材料的化学成分、颗粒尺寸、表面形貌、制备方法等，然而，了解这些特性对微磁行为的影响以操纵吸波性能仍然是一个挑战。本研究以球形和片状磁性吸波材料为研究对象，利用离轴电子全息术研究了磁性吸波材料的形态对磁性的影响。将杂散磁通线可视化，以验证球形和片状金属颗粒之间磁结合形式的差异，从而导致片状金属颗粒的反射损耗(RL)高达-53dB，球形金属颗粒的吸收带宽(>；99%)高达3 GHz。利用离轴电子全息技术进行微场探测，为理解金属复合材料的本征磁性微观行为提供了新的思路。
High permeability and high saturation magnetization are two key attributes to strong microwave absorption for magnetic loss composites, which depend on the chemical composition, particle size, surface profile, fabrication method, etc. However, it is still a challenge to understand the influences of these properties on micro magnetic behaviors to manipulate microwave absorption performances. In this study, magnetic absorbers with spherical and flaky shapes were adapted to investigate the influences of morphology on magnetic properties via off-axis electron holography. Stray magnetic flux lines were visualized to validate the difference in the forms of magnetic incorporation among spherical and flaked-shaped metallic particles, which then results in reflection loss (RL) up to -53 dB for the flakes and absorption ( > 99%) bandwidth up to 3 GHz for the spherical types. The micro-field detection using the powerful technique of off-axis electron holography sheds new light on the understanding about intrinsic magnetic micro behaviors for metallic composites.