Structural, dielectric, and piezoelectric properties of BaTiO3-Bi(Ni1/2Ti1/2)O3 ceramics

Undoped and Mn-doped (1-x)BaTiO3-xBi(Ni1/2Ti1/2)O-3 (x = 0.03-0.7) ceramics were synthesized by a conventional solid state route. X-ray diffraction patterns revealed that the crystal structure was a tetragonal perovskite at x = 0.03, a pseudo-cubic perovskite at x = 0.1 and 0.3, and mixed phases at x = 0.5-0.7. The dielectric and piezoelectric responses were ferroelectric at x = 0.03 and relaxor-like at x = 0.1-0.7. The polarization electric field and strain electric field responses were suppressed at the relaxor compositions, and the large-field piezoelectric constant was 25-40 pm/V at x = 0.3-0.7. As x increased, the temperature of the maximum dielectric constant decreased compared to the Curie temperature of BaTiO3 at x <= 0.1, and then it increased and reached 325 degrees C at x = 0.7. At x = 0.3-0.7, the dielectric constant was less temperature dependent. These results suggest that the samples may be suitable for high temperature capacitor application. (C)2012 The Ceramic Society of Japan. All rights reserved.