Effect of Strontium Doping Into CaBi2Nb2O9 Aurivillius Oxide Nanoceramics: Structural and Electrical Properties

Abstract

Herein, we report the synthesis and characterization of Ca1-xSrxBi2Nb2O9 (CSBNO) (0 ≤ x ≤ 1) nanoceramics prepared using sucrose-assisted sol–gel combustion methods. The synthesized nanoceramics were characterized by different tools like differential thermal and thermogravimetric analyzer (DTA-TG), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FTIR) spectrometer, X-ray powder diffraction (XRD), and impedance analyzer. DTA-TG reveals that the optimum temperature of calcination of CBN is higher than 1000 °C. The FTIR revealed the formation of CaBi2Nb2O9 (CBNO) at 614 cm-1. The XRD confirmed that all samples exhibited orthorhombic crystal structure. Increased orthorhombic distortion was spotted for doped CBNO and the structure acquires extra orthorhombicity through Sr doping. The TEM measurement inspected the increase of the grain size due to the inclusion of strontium into the orthorhombic crystal structure of CBNO from 56 nm to 76 nm. The dielectric constant measurement demonstrated that the increase in Sr content is associated with steady decrease in Curie temperature from 1207 K up to 720 K. The dielectric loss exhibited a minimum value at x = 0.5 and high stability along the temperature range of 300–850 K. Such property may enable this nanocomposite to be used for the application of FeRAM.