多铁性材料Bi1-xBaxFeO3的微波吸收性能

Microwave Absorbing Properties of Multiferroic Bi1-xBaxFeO3

中文关键词: 多铁体 Bi1-xBaxFeO₃ 微波吸收 电磁损耗

英文关键词: multiferroics, Bi1-xBaxFeO₃, microwave absorption, electromagnetic loss

中文摘要:

      用溶胶-凝胶法制备了Bi1-xBaxFeO₃(x=0.0,0.15,0.25,0.35,0.4),用X射线衍射(XRD)和扫描电镜(SEM)表征了样品的晶体结构、微观形貌,用综合物性测试系统(PPMS)测试了样品的室温磁滞回线,用微波矢量网络分析仪测试了样品在2～18 GHz微波频率范围的复介电常数、复磁导率并计算了电磁损耗因子和微波反射率,分析了材料的微波吸收性能和电磁损耗机制。结果表明:Bi1-xBaxFeO₃粉晶呈球状,晶体结构为钙钛矿型,呈较弱的铁磁性；当x=0.35、厚度d=2.7 mm时,在频率f=10.64 GHz位置的吸收峰值为30.43 dB,10 dB带宽为2.4 GHz,微波吸收以介电损耗为主兼具一定的磁损耗。

英文摘要:

      Through sol-gel process,the samples of Bi1-xBaxFeO₃ (x=0.0,0.15,0.25,0.35,0.4) were prepared,whose crystal structure, particle morphology and room-temperature hysteresis loops were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and physical property measurement system (PPMS), respectively. Complex permittivity and complex permeability of the samples were measured by microwave vector network analyzer in the frequency range from 2 GHz to 18 GHz, and reflection coefficient and loss tangent were calcula-ted from measurements. The microwave absorbing properties and the electromagnetic loss mechanism were studied. The result showed that Bi1-xBaxFeO₃ had a perovskite crystal structure, a micro-spherical powder morphology and a weaker ferromagnetism. The absorption peak was 30.43 dB at 10.64 GHz and bandwidth above 10 dB was 2.4 GHz when its thickness was 2.7 mm and x=0.35. The microwave absorption of the samples results from both dielectric loss and magnetic loss but the former is more remarkable.