Nb、K共掺对BiFeO_3纳米晶体结构和磁性的影响  

Effect of Nb and K Co-doping on Crystal Structure and Magnetic Property of BiFeO_3 Nanocrystal

作　　者：杜奕全 邓施列 冼慧敏 张弜[1] 陈熹[1] 

机构地区：[1]华南理工大学物理与光电学院,广州510006

出　　处：《材料导报》2016年第22期43-47,共5页Materials Reports

基　　金：国家自然科学基金(11304098;11504113)

摘　　要：采用溶胶-凝胶法制备Bi_(1-x)K_xFe_(1-x)Nb_xO_3(0≤x≤0.05)纳米晶体,并研究Nb、K共掺杂对BiFeO_3样品晶格结构和磁学性质的影响。根据XRD图谱和Rietveld精修可知,所有样品保持R3c相,晶格常数a、c,晶胞体积V和Fe-O-Fe发生微弱的变化。XPS测量显示,少量的Nb、K共掺杂不引起样品中Fe^(3+)和Fe^(2+)比例的变化。磁测量表明,所有掺杂样品的磁性都得到了增强。当掺杂量x=0.01时,剩余磁化强度Mr达到最大值,Mr=0.1978emu/g,相比于纯BiFeO_3增大了18倍。低掺杂时剩余磁化强度Mr增大,可能是由于掺杂样品中存在束缚磁极化子引起的。Bi1-xKxFe1-xNbxO3 nanocrystal （0≤x≤0.05）were synthesized using a sol-gel method,and the effects of Nb and K co-doping on the lattice structure and magnetic property of BiFeO3 were investigated precisely. The XRD patterns and the Rietveld refinement demonstrate that all the samples maintain the R3c phase while the lat-tice parameters a,c,cell volume V and Fe-O-Fe bond angle change slightly.The XPS reveals that a small amount of Nb and K co-dopant do not change the Fe^3＋ and Fe^2＋ ratio of the doped BiFeO3 samples.Results of the magnetic measurements showed that the magnetic properties of all doped samples are enhanced.The residual magnetization Mr reaches its maximum value at the Nb and K doping concentration x=0.01 and the maximum value is 0.1978 emu/g, which increases 1 8 times compared to pure BiFeO3 .The enhancement of the magnetic property at low doping concen-tration may be attributed to the existence of bound magnetic polaron in the doped samples.

关 键 词：铁酸铋 溶胶-凝胶法 晶体结构 磁学性质 束缚磁极化子 

分 类 号：O76[理学—晶体学]