Microstructure and Dielectric Properties of La-doped Barium Titanate Hafnate Ceramics

Pure and La-doped barium titanate hafnate (BaHf0.1Ti0.9O3, short for BHT) ceramics were prepared by conventional solid state reaction method. The microstructures, dielectric and ferroelectric properties of Ba1-xLaxHf0.1Ti0.9O3 (x = 0, 0.01, 0.02, 0.03, 0.04) ceramics have been investigated. From the x-ray diffraction patterns it is indicated that La3+ ions have entered the unit cell maintaining the perovskite structure of solid solution. After doping with lanthanun the lattice constant increases and the grains become uniform and spherical. The addition of lanthanun leads to the decrease of the Curie temperature. It is found that well-behaved hysteresis loops can be observed in pure BHT ceramics and the hysteresis loops of La-doped BHT ceramics are changed into lines.