Growth of single crystals of 0.75(Na0.5Bi0.5)TiO3-0.25(Sr0.7Ca0.3)TiO3 and characterisation of their electrical properties

Abstract

Single crystals of 0.75(Na0.5Bi0.5)TiO3-0.25(Sr0.7Ca0.3)TiO3 (NBT-25SCT) were grown by top-seeded solid state crystal growth. X-ray diffraction of a polycrystalline ceramic sample and Raman scattering of a single crystal reveal that rhombohedral symmetry is predominant in the structure. The relative permittivity curves of (001), (110) and (111)-oriented single crystals show them to possess relaxor ferroelectric behaviour. The polarization vs. electric field and bipolar strain vs. electric field behaviour of the crystals differ greatly depending on crystallographic orientation. NBT-25SCT single crystals with (111) and (110) orientation show typical ferroelectric/piezoelectric behaviour whereas the (001) orientation initially shows electrostrictive behaviour followed by ferroelectric/piezoelectric behaviour at higher electric fields. Parametric impedance modelling over a wide temperature range is performed by considering mixed ionic and electronic conduction as well as universal dielectric response behaviour. The fitted parameters can represent the features of the raw data, allowing identification of the transition points and associated processes. © 2021 The Author(s)