Ferroelectricity in oxygen-deficient perovskite-type oxide Sr10Ga6Sc4O25

Abstract

We have investigated the physical properties of an oxygen-deficient perovskite-type Sr₁₀Ga₆Sc₄O₂₅ by means of dielectric permittivity, pyroelectric current, and X-ray diffraction (XRD) measurements using a polycrystalline sample. The real part of the dielectric permittivity shows a clear anomaly around 310 K. Switchable pyroelectric current is also observed around this temperature, indicating a ferroelectric phase transition in the title compound. Synchrotron powder XRD measurements reveal that no discontinuous jump takes place in the temperature dependent cell volume around 310 K, implying that the phase transition is of second order. The candidates of the low and high temperature space groups are discussed based on the group theory.