Structural, dielectric, and piezoelectric properties of BaTiO₃–Bi(Ni_1/2Ti_1/2)O₃ ceramics

抄録

Undoped and Mn-doped (1−x)BaTiO₃–xBi(Ni_1/2Ti_1/2)O₃ (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°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.