碱土金属掺杂对BiFeO3陶瓷多铁性的影响

    Effect of Alkaline-earth Metal Ions Doping on the Multiferroic of BiFeO3 Ceramics

    • 摘要: 为了探究碱土金属离子掺杂对BiFeO3陶瓷多铁性的影响,采用固相法成功制备了BiFeO3以及Bi0.9A0.1FeO3(A=Ca、Sr、Ba)陶瓷,并对其铁电、铁磁等性能进行了研究.X射线衍射结果表明:晶体均为六方钙钛矿结构,空间群为R3c,晶胞参数随掺杂离子半径的增大呈现先增大后减小的现象.电学性能测试发现:Bi0.9A0.1FeO3陶瓷的铁电极化值和漏电流密度均随着掺杂离子半径的增大而增大.结合X射线光电子谱(X-ray photoelectron spectroscopy,XPS)铁离子价态分析表明:Bi0.9A0.1FeO3陶瓷铁电性会受掺杂带来的结构畸变和氧空位浓度变化的双重作用的影响.BFO、BCFO、BSFO和BBFO陶瓷的磁化强度依次增大,磁场强度为14 T时磁化强度分别为0.150、0.356、0.497和0.995 emu/g,其铁磁性随掺杂离子半径增大而增强,这与掺杂造成的结构畸变以及铁离子变价有关.

       

      Abstract: To investigate the effect of alkaline-earth metal doping on the multiferroic of BiFeO3 ceramics, BiFeO3 and Bi0.9A0.1FeO3(A=Ca, Sr, Ba) ceramics were successfully prepared by solid phase method, and their ferroelectric as well as ferromagnetic properties were studied. XRD results showed that all samples could be indexed to be the hexagonal perovskite structure with space group R3c. The lattice parameters increase first and then decrease with the increase of the radius of doping ions. Electrical measurements showed that ferroelectric polarization as well as leakage current density of Bi0.9A0.1FeO3 ceramic increases with increasing the radius of doping ions. Taken the XPS analysis into account, we conclude that both structure distortion and the change of oxygen vacancy concentration impact the ferroelectric properties. Under a magnetic field of 14 T the magnetizations of BFO, BCFO, BSFO, BBFO ceramic are around 0.150, 0.356, 0.497 and 0.995 emu/g, respectively. The distortion of the antiferromagnetic structure and the variation of the Fe ions in Bi0.9A0.1FeO3 ceramics are responsible for the enhancement of the ferromagnetism.

       

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