Tb掺杂对BiFeO_3粉晶结构和磁性的影响  

Influence of Tb Substitution on Structure and Magnetism of BiFeO_3 Powders

作　　者：张静[1] 吴玉洁[1] 

机构地区：[1]华南理工大学理学院,广州510006

出　　处：《材料导报》2012年第22期35-38,共4页Materials Reports

基　　金：国家自然科学基金(11104081)

摘　　要：采用溶胶-凝胶法制备了Tb掺杂的BiFeO3粉晶,其掺杂浓度为0≤x≤0.2,分别用X射线衍射仪、Ra-man散射仪和综合物性测量系统对Bi1-xTbxFeO3粉晶样品的结构、Raman活性振动模式和磁性进行了测量和分析。实验结果表明:当Tb掺杂量x在0.10～0.125时,母体BiFeO3的结构由菱形R3c相变为正交Pnma相,同时伴随着铁电-顺电相的变化。另外,随着掺杂浓度的增大,Bi1-xTbxFeO3的磁性逐渐增强,并且在铁电-顺电相相变边界处(x=0.10),剩余磁化强度Mr达到最大值0.223emu/g,约为纯相BiFeO3的8倍。随着Tb掺杂量进一步增大(x≥0.125),样品的剩余磁化强度开始逐渐减小,其原因是在正交相的样品中磁矩逐渐形成了很好的反平行排列。Structural, vibrational, and magnetic properties of Bi1-x, Tbx FeO3（0≤x≤0.2） prepared by sol-gel method were studied by combining X-ray diffraction, Raman scattering, and physical properties measurement. It was found that partial substitution of Tb （x=0.10-0. 125） at Bi site results in a structural transformation from the rhom- bohedral R3c symmetry to the orthorhombic Pnma phase, accompanied by a ferroelectric paraelectric phase transition. In addition, with increasing Tb concentration, the remnant magnetization Mr rises gradually and reaches a maximum of 0. 223emu/g, which is about seven times more than that of the pure BiFeOa, at the polar-nonpolar phase boundary （x=0. 10）. Mr exhibits a gradual decrease with further increasing Tb concentration （x=0. 125）, which is attributed to the anti parallel alignment of magnetic moments in orthorhombic sample.

关 键 词：多铁材料 掺杂 结构相变 磁化强度 

分 类 号：O469[理学—凝聚态物理]