Investigation of structural, electrical and strain properties of [(Bi0.5Na0.5)0.935Ba0.065]1-xZnxTiO3 ceramics

The present study focuses on the synthesis and characterization of the [(Bi_0.5Na_0.5)_0.935Ba_0.065]_1-xZn_xTiO₃ system, successfully synthesized using the solid-state reaction method. X-ray Diffraction (XRD) confirms a homogenous single-phase hexagonal structure with no secondary phase. Rietveld refinement of the XRD data, executed with FullProf software, affirmed the presence of a purely hexagonal phase in all synthesized ceramics, exhibiting robust congruence with the observed patterns, validated by the fitting parameters (Rp, Rwp, Rexp, and χ²). Scanning Electron Microscopy (SEM) images displayed densely packed grains, with average grain sizes increasing from 1.599 μm to 2.303 μm as a function of Zn concentration increases (x = 0–0.04). The Energy Dispersive X-ray (EDX) spectroscopy elucidated the presence of Bi, Ti, Na, Ba O, and Zn in the samples. The dielectric characterization indicated an increase in dielectric maxima alongside a rise in Curie temperature with elevated Zn concentration; However, the depolarization temperature exhibited a reduction, approaching room temperature. It was noted that Zn doping resulted in reduction of the coercive field (E_C) and residual polarization (P_r), which reached minimum values of 30 kV/cm and 22 μC/cm², respectively, at a concentration of x = 0.04. The unipolar strain for BNBZT increased with a concentration of x = 0.02 and subsequently declined with a further increase in dopant concentration.