Lead indium niobate—An antiferroelectric phase

A new phase of lead indium niobate (PbIn1/2Nb1/2O3) is described. The crystal system can be considered as orthorhombic at room temperature with space group Pbam (D9 2 b). A displacive phase transition to the cubic system (space group Pm3m(Ol h)) occurs at 140 ± 5°C. Referred to the perovskite subcell the lattice parameters at room temperature are ap = bp = 4.112 Å, cp = 4.072 Å and γp = 89.81°; above the transition ap = 4.108 Å. The low-temperature phase is found to be isostructural with lead zirconate (PbZrO3). Measurement of dielectric constant with temperature, and measurement of the shift in the transition temperature with applied d.c. field show this phase of lead indium niobate to be antiferroelectric.