BiFeO3-BaTiO3-LaFeO3三元多铁性陶瓷材料的制备及性能研究

Preparation and Properties of Multiferroic BiFeO3–BaTiO3–LaFeO3 Ceramics

摘要:

采用固相法制备了1-x(0.71BiFeO3-0.29BaTiO3)-xLaFeO3 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) 三元多铁性陶瓷材料，并研究了LaFeO3含量对陶瓷物相结构、微观形貌、电学性能和磁电耦合性能的影响。结果显示，所有陶瓷均为单一钙钛矿结构，但随LaFeO3含量的增加，伴随着结构相变。所得陶瓷晶粒尺寸均匀，表现出良好的微观形貌，陶瓷晶粒随LaFeO3含量的增加而明显变小。虽然LaFeO3的加入在一定程度上降低了陶瓷的介电常数，但分析发现，x = 0.1时能降低陶瓷的漏导，其漏电流达到了最小值，大约在10-7~10-8A/cm2数量级，并且该陶瓷的剩余极化强度Pr和磁电耦合系数均达到最大值，分别为0.45?C/cm2和132.21 mV/cm?Oe（120 kHz）。因此，与0.71BiFeO3-0.29BaTiO3陶瓷相比，添加少量LaFeO3时可以一定程度的增加陶瓷的铁电性和磁电耦合性能。

Abstract:

A series of multiferroic 1-x(0.71BiFeO3-0.29BaTiO3)-xLaFeO3 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) ceramics were synthesized by solid state reaction. The effects of LaFeO3 content in 0.71BiFeO3-0.29BaTiO3 system on structure, microstructure, electric and magnetoelectric properties were investigated. All the ceramics form a single phase perovskite structure, and structural phase transition is formed with the increase of LaFeO3. The ceramics show good microscopic appearance. The grain sizes are uniform and decrease obviously with increasing of LaFeO3, which acts as an inhibitor for grain growth. The dielectric constants are decreased by the doping level of LaFeO3. The ceramic of x = 0.1 exhibits low leakage current density J with the value around 10-7~10-8 A/cm2. With the increase of LaFeO3, the remnant polarization and the magnetoelectric coefficient aME of the ceramics attain maximum at x = 0.1, with the value of Pr = 0.45?C/cm2 and aME = 132.21 mV/cm?Oe, respectively. These results suggest that the ferroelectricity properties and ferromagnetism effect can be improved simultaneously by adding suitable LaFeO3.