稀土La^(3+)和Dy^(3+)掺杂BaTiO_3纳米粉体的结构及介电性能研究

Structure and Dielectric Characteristic of BaTiO_3 Nanosize Powder by Doping La^(3+) and Dy^(3+) Ions

采用sol-gel法制备了掺杂不同浓度的稀土La3+、Dy3+离子的纳米BaTiO3粉体样品。通过XRD表征分析了样品的粒度和晶体结构,并通过电容法研究了样品的介电常数及介电损耗因子。研究结果表明,在900℃焙烧2h制备的稀土掺杂纳米BaTiO3:RE3+(RE=La,Dy),粉体的平均粒径在20～40nm之间,比在相同工艺条件下制备的纯纳米BaTiO3粉体的平均粒径明显变小,室温介电常数明显增高。随着稀土离子浓度的增加,纳米BaTiO3:RE3+粉体粒径减小,晶体结构由四方相向立方相转变,其介电常数也随之提高。

The nanosize BaTiO3 powders were fabricated by sol-gel method, which was doped by La^3＋ and Dy^3＋ ions with different concentration respectively. The granularity and the crystal structure of the samples are analysized by XRD, and that the dielectric constant and the dielectric dissipation factor are also studied by the capacitance measurement. These results show that the mean diameter of the BaTiO3：RE^3＋（RE=La, Dy） powders is from 20 to 40nm, which were baked at 900℃ for 2 hours. The mean diameter of the powders becomes obviously smaller than that the pure BaTiO3 powder formed at the same process, whereas the dielectric constant is clearly enhanced at room temperature. The mean diameter of the BaTiO3： RE^3＋ powders is decreased with the concentration of the rare earth ions increased and the phase transformation of the crystal structure is taken place from the cubic to the tetragonal phase and the dielectric constant is increased at the same time.