Temperature stable dielectric properties of lead-free BiFeO3-BaTiO3 modified with LiTaO3 ceramics

LiTaO3 (LT)-modified (1 - x)(0.675BiFeO(3)-0.325BaTiO(3)) + 0.6 mol% MnO2 + 0.4 mol% CuO (BFBTMC-xLT, where x = 0-0.030) ceramics were synthesized by solid state reaction method. The crystal symmetry, ferroelectric response, and temperature stable dielectric properties were investigated as a function of different LT-content. The X-ray diffraction study of BFBTMC-LT piezoceramics revealed no remarkable variation in the crystal symmetry. The value of maximum polarization (P-m approximate to 24 mu C/cm(2)) and remnant polarization (P-r approximate to 18 mu C/cm(2)) were obtained at BFBTMC-0.010LT composition. The maximum temperature of permittivity (T-max) decreased by the addition of LT-content in BFBTMC materials. The un-doped sample was ferroelectric; a change to relaxor behavior occurred by the addition of LT-content, with broad frequency dependent curves of dielectric mid-value permittivity (epsilon(rmid)) and tangent loss as a function of temperature. A significant enhancement occurred at 3 mol% LT-modified BFBTMC ceramics, with epsilon(rmid) = 5000 +/- 9.5% (250-450 degrees C at 1 kHz). These results are favorable for practical applications in high temperature dielectrics. (C) 2018 Elsevier B.V. All rights reserved.