Synthesis, Characterization and Property Evaluation of Single Phase Mg4Nb2O9 by Two Stage Process

Mg4Nb2O9 single phase sample with corundum like hexagonal structure has been successfully synthesized by two stage processes. Thermal characterization of precursors has been studied by TG-DTA. The phase purity is identified by XRD and Raman spectroscopy. The structural analysis has been studied by FESEM, HRTEM including EDX for chemical identification. Optical behaviour is investigated by diffuse reflectance spectroscopy and dielectric property is accessed during investigation. The effect of annealing temperature, phase formation, chemical composition, morphology, band gap energy and dielectric behaviour of single phase Mg4Nb2O9 are examined. Average crystallite size of single phase Mg4Nb2O9 material is around 37.3 and 22 nm from XRD and HRTEM analysis, respectively for the 1000 degrees C treated materials. The direct band gap energy is measured about 3.59 eV from diffuse reflectance spectra of the sample synthesized at 1000 degrees C. Dielectric constant and loss tangent of Mg4Nb2O9 material is observed in the range of 40 Hz-110 MHz frequency.