High Pressure Synthesis, Lattice Distortion, and Dielectric Properties of a Perovskite Bi(Ni 1/2 Ti 1/2 )O 3

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 = 2 a m sin( g /2) = 0.5626(2) nm, b = 4 b m = 1.5681(6) nm, and c = 2 c m cos( g /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 g = 90.80(2), 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.