Ferroelectric Properties of PbZrO3–BiFeO3 Solid Solutions

Abstract

Solid solutions of BiFeO₃ and PbZrO₃ were investigated for crystallographic and dielectric properties. A new pseudocubic perovskite phase was found, which has been tentatively indexed as orthorhombic with the same unit cell as PbZrO₃ but with dielectric properties characteristic of a ferroelectric substance. The Curie point in this series of solid solutions has a minimum of about 155°C at a composition of about (PbZrO₃)_0.80 (BiFeO₃)_0.20, which at room temperature lies on the boundary between the orthorhombic antiferroelectric and the pseudocubic ferroelectric phases. This composition has a relative dielectric constant of 800 at room temperature and shows appreciable dielectric nonlinearity. The Curie point rises to about 400°C for (PbZrO₃)_0.50 (BiFeO₃)_0.50 and is extrapolated to about 900°C for pure BiFeO₃, in agreement with previous data from similar solid solutions. It is felt that this is additional evidence that the distortion from cubic symmetry in BiFeO₃ may be of ferroelectric origin.