Dy掺杂Bi_(1-x)Dy_xFeO_3多铁性材料微波电磁特性研究

Electromagnetic Characteristics of Multiferroic Dy-doped Bi_(1-x)Dy_xFeO_3 in Microwave Range

采用溶胶-凝胶法制备Dy掺杂的Bi1-xDyxFeO3多铁性材料,利用XRD,SEM对材料物相、微结构及形貌进行表征分析;分别采用传输/反射法和弓形法,借助微波矢量网络分析仪测量系统,测量材料试样的微波电磁参量及吸波性能.在实验研究煅烧温度对材料微结构和形貌影响的基础上,确定最佳煅烧温度,进而探讨Dy掺杂量对Bi1-xDyxFeO3材料的微结构、复介电常数和复磁导率频谱特性、电磁损耗机制以及微波吸收性能的影响.结果表明:850oC的煅烧温度制备的Bi1-xDyxFeO3材料杂相基本消失,材料颗粒为亚微米尺寸的短纤维状;Dy掺杂能有效抑制材料中杂相形成和煅烧过程Bi3+挥发,有助于抑制螺旋形自旋磁结构,从而提高复介电常数实部和虚部,增强磁谱的弛豫特性;Bi1-xDyxFeO3材料中介电损耗和磁损耗两种机制共存且存在竞争与协同效应,Dy掺杂可以改善Bi1-xDyxFeO3材料微波高频段的吸波性能.

Multiferroic Bil-xDyxFeO3 with different amounts of doping Dy was prepared in the Sol-gel method. The phase, microstructure and morphology of the samples were characterized with XRD and SEM, respectively. The electromagnetic parameters and microwave absorbing properties were measured respectively in transmission/reflection technique and arc method under the network analyzer system. The optimal calcined temperature was confirmed on the basis of the analysis on the effects of calcined tempera- tures on microstructure and morphology. Further studies were carried out with regard to the influences of Dy-doped contents on microstructure, complex permitivity and permeability, electromagnetic loss mecha- nism and wave absorbing properties. The results indicate that the particles are short fibers in submicron and impurity phases disappear under the calcined temperature of 850 %. The doped Dy can effectively re-strain the formation of the impurity phase, volatilization of Bi3＋, and spiral spin magnetic structure. Therefore, the complex permitivity and relax strength of the permeability spectra are improved. Due to the coexistence and competition of dielectric and magnetic loss mechanism,Bil-xDyxFeOa with doping Dy can improve absorbing ability in high frequency ranges.