Microstructure and Ferroelectric Properties of Ta-Doped Barium Titanate Hafnate Ceramics.

Pure and Ta-doped barium titanate hafnate (BaHf₀₁Ti₀₉O₃, short for BHT) ceramics were prepared by conventional solid state reaction method. The microstructures and ferroelectric properties of BaHf_0.1Ti_0.9-xTa_x0₃ (x = 0, 0.005, 0.01, 0.015, 0.02) ceramics have been investigated. From the x-ray diffraction patterns it is indicated that Ta⁵⁺ ions have entered the unit cell maintaining the perovskite structure of solid solution and the lattice constant of Ta-doped BHT ceramics increases with the increase of Ta content. After doped Ta the grains become closely global or sheet. It is found that both the remanent polarization and the coercive electric field gradually decrease as the Ta content increases from 0.5 mol% to 2 mol%. [ABSTRACT FROM AUTHOR]