High Pressure Synthesis, Lattice Distortion, and Dielectric Properties of a Perovskite Bi(Ni_(1/2)Ti_(1/2))O_3

摘要

A perovskite Bi(Ni_(1/2)Ti_(1/2))O_3 was successfully synthesized under high pressure 6 GPa. This compound has orthorhombic cell with the parameters, a = 2a_m sin(beta/2) = 0.5626(2) nm, b = 4b_m = 1.5681(6) nm, and c = 2c_m cos(beta/2) = 0.5548(2) nm containing eight monoclinic primitive perovskite unit with the parameters, a_m = c_m = 0.39507(7) nm, b_m = 0.39203(15), and beta = 90.80(2) deg, and the lattice distortion is expected to be antiferroelectric. In addition, the sudden increase in the dielectric constant accompanied by the anomaly of dielectric loss was observed at 490 K as the temperature increases. This is though to correspond to the transition from antiferroelectric phase to another one.