Synthesis and Characterization Of Alkaline Earth Based Double Perovskite Compounds

Abstract

Double perovskites such as BaBi2-xFexTiO6 (BBFTO) and MgBi2-xFexTiO6 (MBFTO) with x = 1, 0.8, 0.6, 0.4 and 0.2, were synthesized by the economical solid-state reaction technique at an optimized calcination and sintering temperature. The structural examination of the BBFTO samples by XRD and Rietveld refinement technique using the Fullprof software suggests development of dual phase with major tetragonal (P4mm), and minor monoclinic (P121/c1) crystal system were observed for all BBFTO samples irrespective of varying concentration of Bi3+. However, the structural investigation of MBFTO compounds using the FullProf software identifies structural stability with orthorhombic phase (A21am). The mean crystallite size (D) is decreases with increase in the Bi3+ doping in both of the series. Similarly, developments of polycrystalline features in both series of samples were explored by the SEM study. The surface morphology is quite dense and exhibits less number of voids, while the av. grain sizes increases with Bi3concentrations. Presence of all desired elements with their homogeneously and proportionally distributions over the grains and grain boundaries and absence of any impurity phases were verified through the EDS spectra. Appearances of usual vibrations as of perovskite kind of material were confirmed through the FTIR spectroscopic analysis. The UV-visible study explores higher absorption and lower reflection in the UV and visible range of radiations in both series of samples. Higher threshold wavelength in UV and visible range and increase in the optical band gap are observed by Bi3+ content. The dielectric spectra are very much consistent with the Maxwell-Koop s phenomenological theory. The ambient dielectric property is quite large in BBFTO series, and it is highest in the BaBi1.2Fe0.8TiO6 (x=0.8) with and#603;r~2455 at 100Hz. However, in series-II, the highest value and#603;r~935 was obtained at MgBi1.8Fe0.2TiO6 (x=0.2) at 100 Hz field. Similarly, the RT dielectric loss is lower in both series and it is decreases with the incr