Low temperature synthesis of complex solid solution (1-x)Bi_0.5Na_0.5TiO₃–xBaTiO₃ system: BT induced structural and dielectric anomalies in NBT

Abstract

(1-x)Bi_0.5Na_0.5TiO₃–xBaTiO₃ (NBT-BT) complex solid solutions with different composition of BT (x = 0–0.08, Δx = 0.02) were synthesized by low temperature hydrothermal-combustion route. BT-induced structural distortion in NBT are analyzed by X-ray diffraction (XRD) and Raman spectroscopy (RS) studies. XRD result confirms the presence of morphotrophic phase boundary (MPB) by co-existence of (202) rhombohedral peak and (002)/(200) tetragonal peaks at x = 0.06. However, arisen of new vibration modes at A-site and splitting of bands at B sites at the MPB region are revealed by RS study. Microstructural features of as-developed NBT-BT system exhibit rod-like and cuboid-shape mixed morphology; however BT is found inhibiting grain growth of NBT. The broadening of the dielectric peak with deviation from Curie–Weiss law proves the dielectric dispersion near the MPB region of NBT–BT. BT in NBT causes enhancement in remnant polarization (P_r), suppression in coercive field (E_c) with giant strain (0.27%) at MPB region. Study exhibits potential of nanostructure NBT-BT system to be used as actuators.

KEYWORDS:

• Lead-free piezoceramics system; (1-x) Bi_0.5Na_0.5TiO₃–xBaTiO₃ (NBT-BT) solid solution
• MPB
• Raman spectroscopy
• ferroelectrics
• piezoelectrics

Funding

S.S. acknowledges UGC New Delhi for providing Financial assistance through MANF Fellowship. SAA acknowledge UGC New Delhi, for Finanicial assistance through Raman Fellowship F.No.5-153/2016 (IC).