La掺杂双钙钛矿Ba2NiMoO6的磁性和铁电性能

通过固相烧结工艺制备Ba2-xLaxNiMoO6(x=0,0.1)陶瓷样品,采用多晶X射线衍射仪和扫描电子显微技术对样品的物相成分、晶体结构及其表面形貌进行表征与分析.实验样品的X射线衍射谱与理论模拟多晶样品的X射线标准谱比较,显示样品相已经形成.X射线衍射分析结果表明,Ba2NiMoO6晶体原胞(a=b=c=0.8045 nm)属于立方晶系,空间群为Pm3m,布拉格衍射峰(1,1,1),(3,1,1)分别为样品中Ni离子和Mo离子有序占据B位超晶格有序峰,实验显示La掺杂对样品的晶胞参数影响很小.对样品铁电性能的测试表明,A位的替代增强了Ba2NiMoO6的偶极运动,使剩余极化得到提高.通过振动样品磁强计(VSM)测量样品磁化强度与磁场强度的关系,表明样品在室温下呈现顺磁行为.

Magnetism and ferroelectric properties of La-doping double perovskite Ba2NiMoO6

Polycrystalline double perovskite Ba2NiMoO6 has been synthesized by solid-state reaction.The structure and surface morphology of the sample are investigated by X-ray diffraction and scanning electron microscope.X-ray diffraction(XRD) and subsequent Rietveld refinement confirm that Ba2NiMoO6 is of ordered double perovskite structure with a cubic lattice cell in which a=b=c=0.8045 nm,Ni and Mo ions occupy the B site of double perovskite cell orderly.And the Bragg reflection (1,1,1) and(3,1,1) is identified to be a characteristic feature.The remanent polarization(2Pr) is increased by La-doping.The magnetization curve at room temperature has been measured by vibrating sample magnetometer (VSM).The results indicate that the sample exhibits paramagnetic behavior.