Dielectric and Raman spectroscopic studies of A2ErSbO6 (A = Ba, Sr and Ca)

• Synthesis and structural characterization of double perovskite oxides A2ErSbO6 (A = Ba, Sr, Ca) are performed.
• The Rietveld refinement of XRD profiles suggests that the BES is cubic and SES and CES are monoclinic phase.
• Modified Cole–Cole equation is used to fit the real and imaginary parts of dielectric constant.
• Dielectric constant and conductivity of CES are greater than SES and BES.
• Raman spectroscopy results are correlated with the dielectric data.

Double Perovskite oxides barium erbium antimonate (BES), Ba2ErSbO6, strontium erbium antimonate (SES), Sr2ErSbO6 and calcium erbium antimonate (CES), Ca2ErSbO6 are synthesized by a solid-state reaction technique. Rietveld refinements of the X-ray diffraction data of the samples show that BES crystallizes in cubic structure whereas SES and CES crystallize in monoclinic structure. Fourier transform infrared spectra show two primary modes of the samples at around 415 and 640 cm−1. The vibrational properties of the samples are analyzed by the Raman spectroscopy taken at 488nm wavelength. Group-theoretical study is performed to assign the different vibrational modes of the samples in accordance with the structural symmetry. Dielectric properties of the samples are investigated in a temperature range from 303 K to 553 K and in a frequency range of 50 Hz–1.1 MHz. The frequency dependence of real and imaginary parts of dielectric constant is analyzed using the modified Cole–Cole equation. Frequency dependent conductivity spectra are found to follow the power law. Dielectric spectroscopic results have been correlated with the Raman spectroscopic results.

Raman spectra of BES, SES, CES.Figure optionsDownload as PowerPoint slide