Growth of NBT–BT single crystals by flux method and their structural, morphological and electrical characterizations

Abstract

In this paper, one of the important, eco-friendly polycrystalline material, (1−x)(Na0.5Bi0.5)TiO3 (NBT) – xBaTiO3 (BT) of different compositions (x=0.07, 0.06 and 0.05wt%) around the morphotropic phase boundary (MPB) were synthesized by solid state reaction technique. And the single crystals with 13×7×7mm3, 12×12×7mm3 and 10×7×4mm3 dimensions were grown by self flux method. The morphology, crystal structure and unit-cell parameters have been studied and the monoclinic phase has been identified for 0.07wt% of BT. Higher BT concentration changes the crystal habit and the mechanism has been studied clearly. Raman spectroscopy at room-temperature confirms the presence of functional groups. The quality of the as grown single crystals was examined by high resolution x-ray diffraction analysis. The dielectric properties of the as grown crystals were investigated in the frequency range of 20Hz–2MHz from room temperature to 450°C. The broad dielectric peak and frequency dispersion demonstrates the relaxor behavior of grown crystals. The dielectric constant (εr), transition temperature (Tm), and depolarization temperature (Td) of the grown crystals are found to be comparatively good. The diffusive factor (γ) from Curie–Weiss law confirms the as grown NBT–BT single crystals are relaxor in nature.