稀土La元素掺杂BaTiO_3的晶格调控及铁电性

Lattice Control and Ferroelectric Properties of Rare-earth Element La-doped BaTiO_3

利用溶胶-凝胶法制备了多晶铁电Ba1-xLaxTiO3(x=0,x=0.05,x=0.1,x=0.15,x=0.2)样品,分别用X射线衍射、Raman光谱和铁电分析仪研究分析了样品的结构及铁电性。X射线衍射分析表明La元素掺杂BaTiO3并未引起结构相变,在室温下仍属四方晶系,晶轴比c/a、晶面间距d总体上均随掺La浓度升高而减小,平均晶粒尺寸变化不大;铁电分析表明随着掺La浓度的升高,BaTiO3晶体的铁电性有所被抑制,但粉体仍旧表现出较低的漏电流(10-9 A/cm2)。

We prepared Ba1-xLaxTiO3（x=0,x=0.05,x=0.1,x=0.15,and x=0.2）polycrystalline sample by the sol-gel method.The structure and ferroelectricity of samples were studied by X-ray diffraction,Raman spectra,and ferroelectricity analyzer.The XRD indicates that La doped BaTiO3doesn′t transform its structure,still belonging to tetragonal system at room temperature.The crystal axis ratio c/aand the interplanar space ddecrease with increasing the doping concentration.The ferroelectricity of BaTiO3 crystal is suppressed by increasing concentration of La,but a lower value（10-9 A/cm2）of leakage current is exhibited.